A "Homeric simile," sometimes also called an "epic simile," is a specific kind of simile constantly used by Homer in the Iliad and the Odyssey. Homeric similes take some variation of the form "just like X when it does Y."

Here are a few examples from the Odyssey:

"Out he stalked as a mountain lion exultant in his power strides through the wind and rain and his eyes ablaze and he charges sheep or oxen or chases wild deer but his hunger drives him on to go for flocks, even to raid the best homestead." (Book VI, line 139)

"They cried out, shrilling cries, pulsing sharper than birds of prey - eagles, vultures with hooked claws - when farmers plunder their nest of young too young to fly." (Book XVI, line 247)

"But he himself kept tossing, turning, intent as a cook before some white-hot blazing fire who rolls his sizzling sausage back and forth, packed with fat and blood - keen to broil it quickly, tossing, turning it, this way and that." (Book XX, line 27)

"They panicked - wild, like herds stampeding, driven mad as the darting gadfly strikes in the late spring when the long days come around." (Book XXII, line 311)

"Joy, as warm as the joy that shipwrecked sailors feel when they catch sight of land" (Book XXIII, line 262)