What is "instants"

Usage examples of "instants".

Moonshorn Tower shook all around them for the briefest of instants, with a deep rumbling sound, somewhere a stack of books collapsed with a crash.

Curthas knew the strange foreboding that precedes by instants the sure knowledge that one is going to be.

A thousand times Ilbryn had relived those searing instants of tumbling down the temple, broken and aflame.

Is it not the best of life, that involuntary flash of memory upon instants of the eager past?