Source: r/Euchre Community Discord, #strategy-discussion, October 2025 – November 2026, including seaeagle's simulations.
S1–S4: S1 left of dealer (leads trick 1), S2 dealer's partner, S3 right of dealer, S4 dealer.
R1 / R2: round 1 (order or pick up the upcard), round 2 (name a suit).
Next: the other suit of the upcard's colour. Green / reverse: the two suits of the other colour.
Ruff: trump a trick because you can't follow suit.
Stick: in stick-the-dealer, pass so the dealer must call.
Bird call: ordering a junk hand in R1 to stop the dealer picking up, mainly at 9-9.
Soft donate: a call you expect to lose, made to block a loner, with some chance to make.
Undertrump: play a smaller trump under partner's winning trump, a "no losers" signal.