during (prep.) Look up during at Dictionary.com
late 14c., durand, present participle of obsolete verb duren "to last, endure" (mid-13c.), from Old French durer, from Latin durare "to harden," from durus "hard," from PIE *dru-ro-, suffixed variant form of root *deru- "be firm, solid, steadfast." During the day really is "while the day endures," and the usage is a transference into English of a Latin ablative absolute (compare durante bello "during (literally 'enduring') the war").