Effect of finite duration occurring rapidly (usually in the first \(\pu{24 h}\) or up to \(\pu{14 d}\)) following a single dose or short exposure to a substance or radiation.
Source: PAC, 2007, 79, 1583. (Explanatory dictionary of key terms in toxicology (IUPAC Recommendations 2007)) on page 1593 [Terms] [Paper]