"solid part of a battlement," between and separating two crenelles or embrasures, 1704, from French merlon (17c.), from Italian merlone, augmentative of merlo "battlement," perhaps [OED] a contraction of mergola, diminutive of Latin mergae "two-pronged pitchfork."

"part of the pharynx which is behind and above the soft palate, continuous with the nasal passages," 1873, from naso-, combining form of Latin nasus "nose" (from PIE root *nas- "nose") + pharynx. Related: Nasopharyngeal (1860); nasopharyngitis (1879).

"working or acting for reward, serving only for gain," hence "resulting from sordid motives, ready to accept dishonorable gain," 1530s, from mercenary (n.), or in part from Latin mercenarius "hired, paid, serving for pay."

"one who or that which depresses or pushes down," 1610s, from Latin depressor, agent noun from deprimere "to press down, depress" (see depress). By 1874 as "surgical instrument for pressing down a part of the body."

"peruke, artificial imitation of a head of hair," worn as a fashionable accessory or as part of a professional costume, 1520s, perwyke, a popular corruption of perruck, from French perruque (see peruke), evidently by simulation of the French pronunciation and the influence of peri-.

"divided in three," early 15c., from Latin tripartitus "divided into three parts," from tri- "three" (see three) + partitus, past participle of partiri "to divide" (from pars "a part, piece, a share," from PIE root *pere- (2) "to grant, allot").

"the science of the sounds uttered by the human voice or used in a particular language, phonetics; that part of grammar which treats of pronunciation; the system of sounds and of their combinations in a language," 1799, from phono- + -logy. Related: Phonologist; phonologic.