late 14c., jerarchie, ierarchie, "rank in the sacred order; one of the three divisions of the nine orders of angels;" loosely, "rule, dominion," from Old French ierarchie (14c., Modern French hiérarchie), from Medieval Latin hierarchia "ranked division of angels" (in the system of Dionysius the Areopagite), from Greek hierarkhia "rule of a high priest," from hierarkhes "high priest, leader of sacred rites," from ta hiera "the sacred rites" (neuter plural of hieros "sacred;" see ire) + arkhein "to lead, rule" (see archon). Sense of "ranked organization of persons or things" first recorded 1610s, initially of clergy, sense probably influenced by higher.

1680s, from Medieval Latin hierarchicus, from hierarchia (see hierarchy).

"one who rules in holy things," 1570s, from Medieval Latin hierarcha, from Greek hierarkhia, from hierarkhes "leader of sacred rites, high priest" (see hierarchy).

"a social or governmental hierarchy based on skin tone regardless of race," 1952, usually in a South African context, apparently coined in "The Economist," from pigment + -cracy "rule or government by."

1968, "in a hierarchy, every employee tends to rise to his level of incompetence," named for (and by) Laurence Johnston Peter (1919-1990) Canadian-born U.S. educationalist and author, who described it in his book of the same name (1969).

late Old English, "one who owes allegiance to a sovereign or ruler," from under + diminutive suffix -ling. Middle English had also overling "a superior, one who is superior in a hierarchy" (mid-14c.).

"the beaten dog in a fight," 1887, from under + dog (n.). Compare top dog "dominant person in a situation or hierarchy" (see top (adj.)). Its opposite, overdog, is attested by 1908.

I'm a poor underdog

But tonight I will bark

With the great Overdog

That romps through the dark.

[from "Canis Major," Robert Frost, 1928] 

1570s, "arrange in lines;" 1590s, "put in order, classify; assign a rank to," also "have a certain place in a hierarchy," from rank (n.). The meaning "outrank, take precedence over" is by 1841. Related: Ranked; ranking. An earlier verb ranken (mid-13c.) "to fester, suppurate" is from rank (adj.).

mid-12c., pekking, "the pecking of birds," verbal noun from peck (v.). As a description of a pattern of behavior among hens, pecking order (1928) translates German hackliste (T.J. Schjelderuo-Ebbe, 1922); the transferred sense of "human hierarchy based on rank or status" is by 1955.

1580s, "believer in a mystical religious doctrine of spiritual knowledge," from Late Latin Gnosticus "a Gnostic," from Late Greek Gnōstikos, noun use of adjective gnōstikos "knowing, able to discern, good at knowing," from gnōstos "known, to be known," from gignōskein "to learn, to come to know," from PIE root *gno- "to know." Applied to various early Christian sects that claimed direct personal knowledge beyond the Gospel or the Church hierarchy; they appeared in the first century A.D., flourished in the second, and were stamped out by the 6th.