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decay: decay: [15] The notion underlying decay and its close relative decadence is of a ‘falling off’ from a condition of health or perfection. Decay comes from Old Northern French decair, a descendant of Vulgar Latin *dēcadere, which in turn came from Latin dēcidere, a compound verb formed from the prefix dē- ‘down, off, away’ and cadere ‘fall’ (source of English case and a wide range of related words). Decadence [16] was acquired via the medieval derivative dēcadentia. To the same word-family belongs deciduous [17], from Latin dēciduus, literally denoting the ‘falling off’ of leaves from trees.
=> accident, case, chance, decadence, deciduous
Clyde: masc. proper name, from the family name, from the region of the Clyde River in Scotland (see Clydesdale). Most popular in U.S. for boys c. 1890-1910, falling off rapidly thereafter, hence probably its use in 1940s teenager slang for "a square, one not versed in popular music or culture."
falling (adj.): present participle adjective from fall (v.). Falling star is from 1560s; falling off "decrease, declining" is from c. 1600. Falling evil "epilepsy" is from early 13c.
log (n.1): unshaped large piece of tree, early 14c., of unknown origin. Old Norse had lag "felled tree" (from stem of liggja "to lie"), but on phonological grounds many etymologists deny that this is the root of English log. Instead, they suggest an independent formation meant to "express the notion of something massive by a word of appropriate sound." OED compares clog (n.) in its original Middle English sense "lump of wood." Log cabin (1770) in American English has been a figure of the honest pioneer since the 1840 presidential campaign of William Henry Harrison. Falling off a log as a type of something easy to do is from 1839.
stake (n.1): "pointed stick or post," Old English staca "pin, stake," from Proto-Germanic *stakon (cognates: Old Norse stiaki, Danish stage, Old Frisian stake, Middle Dutch stake, Dutch staak, German stake), from PIE root *steg- (1) "pole, stick." The Germanic word has been borrowed in Spanish (estaca), Old French (estaque), and Italian stacca) and was borrowed back as attach.

Meaning "post upon which persons were bound for death by burning" is recorded from c. 1200. Meaning "vertical bar affixed to the edge of a platform of s truck, rail car, etc., to hold boards to keep the load from falling off" is from 1875; hence stake-body as a type of truck (1907). In pull up stakes, "The allusion is to pulling up the stakes of a tent" [Bartlett].
apoptosis: "The death of cells which occurs as a normal and controlled part of an organism’s growth or development", 1970s: from Greek apoptōsis 'falling off', from apo 'from' + ptōsis 'falling, a fall'.