Uttering a statement or declaration which is proven to be false is a crime in many jurisdictions, though usually a separate offence from perjury.
The word declarant, when discussing the hearsay rule and its exceptions, refers to the person who makes an out-of-court statement. For example, if John is on the witness stand and says "Mary said that she was afraid." Mary is the declarant, not John. This concept is important in understanding many applications of the hearsay rule and its exceptions.