The main categories of development that children and adolescents experience over time, such as physical, social, social and emotional development. Various professions and legal documents name and categorize areas of child development in a variety of ways. 

The process by which an individual experiences physical, cognitive, social, and emotional changes from infancy through late adolescence. The prenatal period also affects child development.

Theories put forth by psychologists and others seeking to understand, explain and predict behaviors over the lifespan of a person's development. Well-known examples are Freud’s psychosexual developmental theory, Erikson’s psychosocial developmental theory, Watson's and Skinner's behavioral child development theories, Piaget’s cognitive developmental theory, Bowlby's attachment theory, Bandura's social learning theory, and Vygotsky's sociocultural theory. Theories once assumed to be universal in developmental sciences, such as attachment, are now recognized to vary by culture and experience.  

Progressive change over time in one or more areas of child development (e.g., physical, cognitive, social and emotional). Note: While some fields use  "growth" and "development" interchangeably, others distinguish between physical growth (increase in body size) and physical development (increase in control of the body).

A type of learning in which an initially neutral stimulus (the "conditioned stimulus"), when paired with a stimulus that elicits a reflex response (the "unconditioned stimulus"), results in a learned (conditioned) response. For example, a dog's mouth normally waters when he tastes food. But if a trainer uses a tone just before providing the food, and repeats this conditioning several times, eventually the dog's mouth will water when he hears the tone, even if no food is presented. Also called Pavlovian conditioning, as it was discovered by Soviet physiologist Ivan Pavlov. 

The construction of thought processes, problem solving, and decision-making from childhood through adolescence to adulthood. Includes other intellectual abilities such as memory, language and reasoning. Cognitive development determines how a person perceives, thinks and gains understanding of their world. One of four interrelated areas of child development, along with physical, social, and emotional development. 

The patterns of beliefs, practices and traditions associated with a group of people. Culture affects a child's development; societal, institutional and cultural norms for developmental stages may differ.

The things most children can do by a certain age or stage of development. For example: taking a first step, communicating in complete sentences and understanding abstract ideas.

Practices educators and caregivers use to promote a child’s optimal development and learning, taking into account the child's current abilities and stage of development. The National Association for Young Children describes it as "a strengths-based, play-based approach to joyful, engaged learning."

Generally defined as a physical, mental, cognitive, or developmental condition that impairs, interferes with, or limits a person's ability to engage in certain tasks or actions or participate in typical daily activities and interactions. The Individuals with Disabilities Education Act (IDEA) states that a "child with a disability means a child evaluated in accordance with §§300.304 through 300.311 as having an intellectual disability, a hearing impairment (including deafness), a speech or language impairment, a visual impairment (including blindness), a serious emotional disturbance (referred to in this part as “emotional disturbance”), an orthopedic impairment, autism, traumatic brain injury, an other health impairment, a specific learning disability, deaf-blindness, or multiple disabilities, and who, by reason thereof, needs special education and related services." IDEA states it can also include a child 3-9 years old who's experiencing a developmental delay. See "developmental delay."

A child’s growing ability to regulate and control their emotions and to form secure relationships; to recognize, express, and manage feelings at different stages of life; and to have empathy for the feelings of others. One of four interrelated areas of child development, along with physical, cognitive and social development. 

Attention-regulation skills that make it possible to sustain attention, keep goals and information in mind, refrain from responding immediately, resist distraction, tolerate frustration, consider the consequences of different behaviors, reflect on past experiences, and plan for the future. 

The movement and control of the small muscles of the body, such as those in the hands and fingers (e.g., to write with a pencil or use scissors).

The ability to move and control large muscles or groups of muscles, such as those in the arms, legs or torso (e.g., to sit, crawl, walk or run).

The cumulative emotional and psychological wounding over the lifespan and across generations, emanating from massive group trauma experiences. Examples include the multigenerational effects of White supremacy reflected in colonization, genocide, slavery, sexual exploitation, forced relocation, and incarceration based on race or ethnicity.

The things most children can do by a certain age or stage of development. For example: taking a first step, communicating in complete sentences and understanding abstract ideas.

A phrase often used to describe how a person's characteristics and development are affected by nature (genetics) versus nurture (environment, which includes factors like caregiver interaction, physical and psychological safety, nutrition, exercise, education, culture, and access to various opportunities and resources).

The process in which behavioral change (i.e., learning) occurs as a function of the consequences of behavior. For example: Rewarding behavioral change in a misbehaving child. Also called operant learning. First described by psychologist B. F. Skinner.

A form of play in which two children next to each other engage in similar types of play but don't interact with each other. It's one of the six stages of play identified by sociologist Mildred Parten: unoccupied, solitary, onlooker, parallel, associative, cooperative.

A person's characteristic patterns of thinking, feeling and behaving. In psychology, the study of personality focuses on two broad areas (a) understanding individual differences in particular personality characteristics, such as sociability or irritability, and (b) understanding how the various parts of a person come together as a whole.

Development and coordination of gross motor skills (mastery of large muscle movement, such using the arms and legs to play a sport) and fine motor skills (mastery of small muscle movement, such using the hands and fingers to manipulate objects). One of four interrelated areas of child development, along with cognitive, social and emotional development. 

Productive and constructive engagement that promotes positive outcomes by providing opportunities, fostering positive relationships and supporting young people to build on their strengths. A framework for the practice of social and emotional learning.

The period between conception and birth.

Development in two closely related areas: social and emotional. See "social development" and "emotional development." 

Time periods during which children develop physically, cognitively, socially and emotionally. The stages may be described as a series of overlapping periods of development: prenatal (conception through birth), infancy (birth to age 2), early childhood (ages 2-6), middle childhood (ages 6-9), late childhood/early adolescence (ages 9-12), middle adolescence (ages 12-15); and late adolescence (ages 15-18).  

The basic foundation of personality, usually assumed to be biologically determined and present early in life, including such characteristics as energy level, emotional responsiveness, demeanor, mood, response tempo, behavioral inhibition and willingness to explore.

The gap between what a person can do with help and what they can do on their own. This concept was developed by Lev Vygotsky.