Old English brand, brond "fire, flame, destruction by fire; firebrand, piece of burning wood, torch," and (poetic) "sword," from Proto-Germanic *brandaz "a burning" (source also of Old Norse brandr, Old High German brant, Old Frisian brond "firebrand; blade of a sword," German brand "fire"), from PIE root *gwher- "to heat, warm."

Meaning "iron instrument for branding" is from 1828. Meaning "mark made by a hot iron" (1550s), especially on a cask, etc., to identify the maker or quality of its contents, broadened by 1827 to marks made in other ways, then to "a particular make of goods" (1854). Brand-name is from 1889; brand-loyalty from 1961. Old French brand, brant, Italian brando "sword" are from Germanic (compare brandish).

"spirits distilled from other liquors" (especially wine), 1650s, abbreviation of brandy-wine (1620s) from Dutch brandewijn "burnt wine," earlier brand-wijn, so called because it is distilled (compare German cognate Branntwein and Czech palenka "brandy," from paliti "to burn"). The Brandywine Creek in Pennsylvania, site of the 1777 Revolutionary War battle, supposedly was so named 17c. by the Dutch explorers for the color of its waters.

In familiar use abbreviated as brandy as early as 1657; but the fuller form was retained in official use (customs tariffs, acts of parliament, etc.) down to the end of 17th c., being latterly, as the spelling shows, regarded as a compound of brandy + wine. [OED]

"sulfur in a solidified state," Old English brynstan, from brin- stem of brinnen "to burn" (from Proto-Germanic *brennan "to burn," from PIE root *gwher- "to heat, warm") + stan (see stone (n.)). In Middle English the first element also recorded as brem-, brom-, brum-, bren-, brin-, bron-, brun-, bern-, born-, burn-, burned-, and burnt-. Formerly "the mineral sulfur," now restricted to biblical usage.

The Lord reynede vpon Sodom and Gomor brenstoon and fier. [Wycliff's rendition (1382) of Genesis xix.24]

The Old Norse cognate compound brennusteinn meant "amber," as does German Bernstein.

goddess of ovens in ancient Rome, from Latin fornax "furnace, oven, kiln" (from PIE root *gwher- "to heat, warm"). The dim constellation (representing a chemical furnace) was created by French astronomer Nicolas Louis de La Caille in 1752.

c. 1300, from Old French fornicacion "fornication, lewdness; prostitution; idolatry" (12c.), from Late Latin fornicationem (nominative fornicatio), noun of action from past-participle stem of fornicari "to fornicate," from Latin fornix (genitive fornicis) "brothel" (Juvenal, Horace), originally "arch, vaulted chamber, a vaulted opening, a covered way," probably an extension, based on appearance, from a source akin to fornus "brick oven of arched or domed shape" (from PIE root *gwher- "to heat, warm"). Strictly, "voluntary sex between an unmarried man and an unmarried woman;" extended in the Bible to adultery. The sense extension in Latin is perhaps because Roman prostitutes commonly solicited from under the arches of certain buildings.