n (chemistry) a process in which one or more substances are changed into others
n an idea evoked by some experience
n a bodily process occurring due to the effect of some antecedent stimulus or agent
n (mechanics) the equal and opposite force that is produced when any force is applied to a body
n a response that reveals a person's feelings or attitude
n extreme conservatism in political or social matters
n doing something in opposition to another way of doing it that you don't like