(chemistry) any theory in which all matter is composed of tiny discrete finite indivisible indestructible particles; "the ancient Greek philosophers Democritus and Epicurus held atomic theories of the universe"
(psychology) a theory that reduces all mental phenomena to simple elements (sensations and feelings) that form complex ideas by association
the act of noticing or paying attention; "he escaped the notice of the police"
polite or favorable attention; "his hard work soon attracted the teacher's notice"
a short critical review; "the play received good notices"
an announcement containing information about a future event; "you didn't give me enough notice"
advance notification (usually written) of the intention to withdraw from an arrangement or contract; "we received a notice to vacate the premises"; "he gave notice two months before he moved"
express recognition of the presence or existence of, or acquaintance with; "He never acknowledges his colleagues when they run into him in the hallway"; "She acknowledged his complement with a smile"; "it is important to acknowledge the work of others in one's own writing"
notice or perceive; "She noted that someone was following her"; "mark my words"
a statement that makes something comprehensible by describing the relevant structure or operation or circumstances etc.; "the explanation was very simple"; "I expected a brief account"
the act of explaining; making something plain or intelligible; "I heard his explanation of the accident"