以来
いらい · irai · JLPT N3 · noun
since
⏳ 以来 = from (以) + come (来): everything that has come since then
以 marks a starting point and 来 means come, so 以来 is the time that has come from that point on. It goes after the event: 卒業以来 means since graduation. Don't mix it up with 依頼 (irai, a request), which sounds the same.
以 — phonetic 㠯 (plow/tool) + 人 (person)
Originally a pictograph of a hand-held plow or tool (㠯), later combined with 人 (person) to suggest 'using' something. The core meaning 'to use' extended metaphorically to 'by means of', 'with', and 'because of'. In modern Chinese it functions mainly as a grammatical particle.
来 — pictograph of a wheat plant with grain heads
来 originally depicted a stalk of wheat with drooping grain heads, and meant 'wheat' in oracle bone script. It was later borrowed phonetically to write the unrelated verb 'to come,' which became its dominant meaning. The original 'wheat' sense was taken over by 麥 (now 麦).