the average time that an unstable particle or nucleus survives before it decays.
(physics) the average time of existence of an unstable or reactive entity, such as a nucleus, elementary particle, charge carrier, etc; lifetime. It is equal to the half-life divided by 0.693 15 τ
noun, Printing. 1. an imaginary x-high line.
[meen-lee] /ˈmin li/ adverb 1. in a poor, lowly, or humble manner. 2. in a base, contemptible, selfish, or shabby manner. 3. in a stingy or miserly manner. [meen-lee] /ˈmin li/ adverb, Obsolete. 1. . adv. 1580s, “indifferently;” 1590s, “basely;” c.1600, “illiberally;” from mean (adj.1) + -ly (2).
- Mean machine
noun a team or other group thought to be unbeatable or extremely powerful
[meen-nis] /ˈmin nɪs/ noun 1. the state or quality of being . 2. a act: to answer meannesses with forgiveness. n. 1550s, “weakness,” from mean (adj.) + -ness. Sense of “baseness, poverty” is from 1650s; that of “stinginess” from 1755.
noun, Astronomy. 1. the moment when the mean sun’s center crosses the meridian.