This article is from the Magic: The Gathering Rules FAQ, by Patrik Linell (pls@claymore.nu) with numerous contributions by others.
To "play" a spell or ability means to announce it, as I said
above. In other words, you pay its costs, choose its targets, and put it
onto the stack. To "put a card into play" means to put it into the "in
play" zone.
This means that it's possible to "play" an Instant or Sorcery spell, but
not possible to "put it into play". A spell or ability that tells you to
"put a creature into play", such as Dragon Arch, is not telling you to
"play" it.
 
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