mucus (n.)

"stick for striking fire." Late 14c., macche, "wick of a candle or lamp," a sense now obsolete, from Old French meiche "wick of a candle," from Vulgar Latin *micca/*miccia (source also of Catalan metxa, Spanish mecha, Italian miccia), which is of uncertain origin, probably ultimately from Latin myxa, from Greek myxa "lamp wick," originally "mucus," based on notion of wick dangling from the spout of a lamp like snot from a nostril, from PIE root *meug- "slimy, slippery" (see mucus). English snot also had a secondary sense from late 14c. of "snuff of a candle, burnt part of a wick," surviving at least to late 19c. in northern dialects.

The modern spelling is from mid-15c. The meaning "piece of cord or tow soaked in sulfur, used for lighting fires, lamps, candles, etc." is from 1530. It was used by 1830 for the modern type of sulfur-tipped wooden friction match, which were perfected about that time, and competed with lucifer for much of 19c. as the name for this invention. An earlier version consisted of a thin strip of wood tipped with combustible matter that required contact with phosphorous carried separately in a box or vial.

In the manufacture of matches much trouble has been occasioned by the use of phosphorous .... In some of the small and poorly-managed factories the men and children are never free from the fumes; their clothes and breath are luminous in the dark, and in the daytime white fumes may be seen escaping from them whenever they are seated by the fire. ... The danger arising from the use of matches was magnified, because they could sometimes be seen in the dark, were liable to ignite on a warm shelf, and were poisonous to such an extent that children had been killed by using them as playthings. [John A. Garver, "Matches," in The Popular Science Monthly, August 1877]

late 14c., "slightly wet; well-irrigated, characterized by moistness," from Old French moiste "damp, wet, soaked" (13c., Modern French moite), which is of uncertain origin. Perhaps from Vulgar Latin *muscidus "moldy," also "wet," from Latin mucidus "slimy, moldy, musty," from mucus "slime" (see mucus). Alternative etymology [Diez] is from Latin musteus "fresh, green, new," literally "like new wine," from musteum "new wine" (see must (n.1)). If this wasn't the source, it influenced the form of the other word in Old French. Related: Moistly; moistness (mid-14c.).