To play a card means to play that card as a land or to cast that card as a spell, whichever is appropriate.
July 3, 2020 · Core Set 2021
If a player is instructed to scry 0, no scry event occurs. Abilities that trigger whenever a player scries won’t trigger.
May 3, 2019 · War of the Spark
If a player is searching a hidden zone for cards with a stated quality, such as a card with a certain card type or color, that player isn’t required to find some or all of those cards even if they’re present in that zone.
January 25, 2019 · Ravnica Allegiance
If a player is searching a hidden zone for cards with a stated quality, such as a card with a certain card type or color, that player isn't required to find some or all of those cards even if they're present in that zone.
April 27, 2018 · Dominaria
If a player is searching a hidden zone for cards with a stated quality, such as a card with a certain card type or color, that player isn’t required to find some or all of those cards even if they’re present in that zone.
September 30, 2016 · Kaladesh
Some effects cause a player to search a library for a card or cards, shuffle that library, then put the found card or cards in a certain position in that library. Even though the found card or cards never leave that library, they aren’t included in the shuffle. Rather, all the cards in that library except those are shuffled. Abilities that trigger when a library is shuffled will still trigger. See also rule 401, “Library.”
September 26, 2015 · Battle for Zendikar
If a player is instructed to scry 0, no scry event occurs. Abilities that trigger whenever a player scries won’t trigger.