"next in order after the fifth; an ordinal numeral; being one of six equal parts into which a whole is regarded as divided;" 1520s, replacing Middle English sixte (c. 1200), from Old English syxte, from siex (see six). Compare Old Frisian sexta, Middle Dutch seste, Old High German sehsto, German sechste, Gothic saihsta. With ending conformed to -th (1). Related: Sixthly. The noun meaning "a sixth part" is from 1550s. As a music tone, from 1590s. Sixth sense "supernatural perception of objects" is attested from 1712; earlier it meant "titillation, the sense that apprehends sexual pleasure" (1690s, from Scaliger).
Then said Peter, That is false; for there is a sixth Sense, that of Prescience : for the other five Senses are capable only of Knowledg ; but the Sixth of Foreknowledg ; which Sense the Prophets had. [William Whitson, "Primitive Christianity Reviv'd," vol. v, London, 1712]
1590s, "perceive (an object) by the senses," from sense (n.). The meaning "be conscious inwardly of" (one's state or condition) is from 1680s. The sense of "perceive or understand (a fact or situation) not by direct perception" is from 1872. Related: Sensed; sensing.
late 14c., "meaning, signification, interpretation" (especially of Holy Scripture); c. 1400, "the faculty of perception;" from Old French sens "one of the five senses; meaning; wit, understanding" (12c.) and directly from Latin sensus "perception, feeling, undertaking, meaning," from sentire "perceive, feel, know."
This probably is a figurative use of a literal meaning "find one's way," or "go mentally." According to Watkins and others, this is from a PIE root *sent- "to go" (source also of Old High German sinnan "to go, travel, strive after, have in mind, perceive," German Sinn "sense, mind," Old English sið "way, journey," Old Irish set, Welsh hynt "way").
The application to any one of the external or outward senses (touch, sight, hearing, any special faculty of sensation connected with a bodily organ) in English is recorded from 1520s. They usually are reckoned as five; sometimes a "muscular sense" and "inner (common) sense" are added (perhaps to make the perfect seven), hence the old phrase the seven senses, sometimes meaning "consciousness in its totality." For the meaning "consciousness, mind generally," see senses.
The meaning "that which is wise, judicious, sensible, or intelligent" is from c. 1600. The meaning "capacity for perception and appreciation" also is from c. 1600 (as in sense of humor, attested by 1783, sense of shame, 1640s). The meaning "a vague consciousness or feeling" is from 1590s.
late 14c., originally an internal mental power supposed to unite (reduce to a common perception) the impressions conveyed by the five physical senses (Latin sensus communis, Greek koine aisthesis). Thus "ordinary understanding, without which one is foolish or insane" (1530s); the meaning "good sense" is from 1726. Also, as an adjective, common-sense "characterized by common sense" (1854).
instrument for determining latitude in navigation and surveying, 1620s, from Modern Latin sextans, which is said to have been first used in this sense c. 1600 by Danish astronomer Tycho Brahe, from Latin sextans "a sixth, a sixth part," from sex "six" (see six). So called because the sextans has a graduated arc equal to a sixth part of a circle. In ancient Rome, sextans also was the name of a coin of the republic worth one-sixth of an as. Related: Sextantal.
1580s (n.); 1590s (adj.), in reference to Roman leap year, from Late Latin (annus) bisextilis "leap year," more literally "the twice sixth-day, (a year) containing a second sixth (day)." To keep the Julian calendar consistent with the sun, the sixth day (by inclusive reckoning) before the Calends of March was doubled every four years. The date corresponds to our February 24th. From Latin bissextus/bisextis (dies), from bis "twice" (see bis-) + sextus "sixth (day before the First of March)," from sex "six" (see six).