trade vs all in
The way back. A trade is a short exchange, after which both step back; an all-in commits everything, with no way back. Trades set up the all-in.
trade
Trading is exchanging a bit of damage in lane: a spell, an attack, and you step back. The goal is to come out of the exchange with more health than the other, trade after trade, until they can no longer stay. "good trade", "dont trade he has ignite".
open the page →all in
All-in is committing everything: every spell, flash, ignite, with no possibility of backing out. You all-in when the enemy is low enough to die, often at level 6 or after a string of won trades. "all in at 6". A failed all-in ends in a death, usually yours.
open the page →Why they get mixed up
A trade that goes well makes you want to keep going, and that is how a trade becomes an all-in nobody decided on. The difference is a decision, not a degree: before an all-in, you have counted spells, summoners and health on both sides. Before a trade, you just saw an opening.