From Ancient Times, Age-Old
adverb, noun, の adjective
Things that are really old come from ancient times! This is a relatively formal expression that’s used to talk about age-old things, like customs that have stood the test of time.
こらい
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
古来から、あの山は「ふじ山」という名だ。
Since ancient times, that mountain has been called "Mt. Fuji."
カッパは、日本古来のヨウカイです。
The kappa is an ancient Japanese yokai.
竹を用いるのは、古来のDIYの仕方です。
Using bamboo is the ancient way of DIY.