latitude (n.) Look up latitude at Dictionary.com
late 14c., "breadth," from Old French latitude (13c.) and directly from Latin latitudo "breadth, width, extent, size," from latus "wide, broad, extensive," from Old Latin stlatus, from PIE *stleto-, suffixed form of root *stele- "to spread, to extend" (source also of Old Church Slavonic steljo "to spread out," Armenian lain "broad"). Geographical and astronomical senses also are from late 14c., literally "breadth" of a map of the known world. Figurative sense of "allowable degree of variation, extent of deviation from a standard" is early 15c. Related: Latitudinal "pertaining to geographic latitude" (1778).