Your favorite word could be our Word of the Day!
early 15c., "impervious to water," from Old French estanche "firm, watertight," fem. of estanc "dried, exhausted, wearied, vanquished," from Vulgar Latin *stanticare, probably from Latin stans (genitive stantis), present participle of stare "to stand," from PIE root *sta- "to stand" (see stet). Sense of "strong, substantial" first recorded mid-15c.; of persons, "standing firm and true to one's principles" from 1620s.