Blank verse is a type of poetry that has a regular meter, usually iambic pentameter, but no rhyme. Most of Shakespeare’s plays are written in blank verse.
English writers have been using blank verse since the 16th century. For example, in Paradise Lost Milton described the Adam and Eve story: “But suddenly with flesh fill’d up and heal’d: / The Rib he formd and fashoned with his hands.” The lines have a standard iambic rhythm to them but "heal'd" and "hands" definitely don't rhyme, so you know that's blank verse. Poets in more recent times continue to use blank verse.