Select (Japanese: 選択sentaku) is an outdated term in the TCG (the OCG term is still used) used in card texts prior to the Problem-Solving Card Text update. "Select" indicates that a player decides which card is affected.
"Select" usually indicated that a card targets (the absence of "select" did not mean a card does not target). Some cards that used to say "select", such as "Creature Swap" and "A Cat of Ill Omen", do not target; such cards now use "choose" to specify that a player decides which card without targeting.
An old print of "Creature Swap" which uses "select".
A more recent print of "Creature Swap" which now uses "choose".