early 12c., "small monastery, subordinate monastery" (from Medieval Latin in this sense), later "small room for a monk or a nun in a monastic establishment; a hermit's dwelling" (c. 1300), from Latin cella "small room, store room, hut," related to Latin celare "to hide, conceal" (from PIE root *kel- (1) "to cover, conceal, save").
From "monastic room" the sense was extended to "prison room" (1722). The word was used in 14c., figuratively, of brain "compartments" as the abode of some faculty; it was used in biology by 17c. of various cavities (wood structure, segments of fruit, bee combs), gradually focusing to the modern sense of "basic structure of all living organisms" (which OED dates to 1845).
Electric battery sense is from 1828, based on the "compartments" in very early types. The meaning "small group of people working within a larger organization" is from 1925. Cell-body is from 1851, cell-division from 1846, cell-membrane from 1837 (cellular membrane is by 1732), cell wall is attested from 1842.
Old English blod "blood, fluid which circulates in the arteries and veins," from Proto-Germanic *blodam "blood" (source also of Old Frisian blod, Old Saxon blôd, Old Norse bloð, Middle Dutch bloet, Dutch bloed, Old High German bluot, German Blut, Gothic bloþ), according to some sources from PIE *bhlo-to-, perhaps meaning "to swell, gush, spurt," or "that which bursts out" (compare Gothic bloþ "blood," bloma "flower"), from suffixed form of root *bhel- (3) "to thrive, bloom." But Boutkan finds no certain IE etymology and assumes a non-IE origin.
There seems to have been an avoidance in Germanic, perhaps from taboo, of other PIE words for "blood," such as *esen- (source of poetic Greek ear, Old Latin aser, Sanskrit asrk, Hittite eshar); also *krew-, which seems to have had a sense of "blood outside the body, gore from a wound" (source of Latin cruour "blood from a wound," Greek kreas "meat"), but which came to mean simply "blood" in the Balto-Slavic group and some other languages.
Inheritance and relationship senses (also found in Latin sanguis, Greek haima) emerged in English by mid-13c. The meanings "person of one's family, race, kindred; offspring, one who inherits the blood of another" are late 14c. As the fluid of life (and the presumed seat of the passions), blood has stood for "temper of mind, natural disposition" since c. 1300 and been given many figurative extensions. The slang meaning "hot spark, a man of fire" [Johnson] is from 1560s. Blood pressure is attested from 1862. Blood money is from 1530s; originally money paid for causing the death of another.
Blood type is from 1928. That there were different types of human blood was discovered c. 1900 during early experiments in transfusion. To get blood from a stone "do the impossible" is from 1660s. Expression blood is thicker than water is attested by 1803, in reference to family ties of those separated by distance. New (or fresh) blood, in reference to new members of an organization or group, especially ones bringing new ideas and fresh vigor or strength, is from 1880.
1590s, "to smear or stain with blood;" 1620s, "to cause to bleed," from blood (n.). Meaning "to give (a hunting animal) its first taste of blood" is from 1781. Related: Blooded; blooding.
1809 in reference to the blood that flows in the veins of the old and aristocratic families of Spain, translating Spanish sangre azul, claimed by certain families of Castile that held themselves uncontaminated by Moorish or Jewish admixture; the term probably is from the notion of the visible veins of people of fair complexion. In reference to English families by 1827. As a noun, "member of an old and aristocratic family," by 1877. See blue (adj.1) + blood (n.).
also bloodcurdling, figurative, "chilling the blood; causing thrills of fear or horror," 1817, from blood (n.) + present participle of curdle. Also formerly with a noun form, bloodcurdler "incident which freezes the blood," especially "sensational story," 1877, slang; also in use in this sense was blood-freezer (1886).
