You can think of glean as a field after the harvest. The crop has been cut and carried off, the cart is gone, and what is left is scattered flat on the ground: a grain here, a potato there, one missed fruit under a leaf. Anyone who wants those has to walk the ground and pick them up one at a time, bending for each one. Nothing is handed over in a sack. Wherever this word goes, those three things go with it — the pieces are small, they are taken off a surface, and the work is slow.
From the word’s history
The packet's Wiktionary etymology takes the verb from Late Middle English glenen, from Old French glener, from Late Latin glen(n)ō 'to make a collection', with the earliest recorded use being the harvest one. So the field is not a metaphor added later — it is where the word starts.
依照本次提供的維基詞典字源，這個動詞來自晚期中古英文 glenen，再往前是古法文 glener，更早是晚期拉丁文 glen(n)ō（把東西收集起來），而最早記錄下來的用法就是田裡的拾穗。所以那片田不是後人加上去的比喻，它就是這個字出發的地方。
Wiktionary etymology supplied in this packet (source_ref kaikki:3f6f69a190036ae4:402256369)
登入就可以看每一支怎麼連回核心畫面。