In linguistics, a filler, filled pause, hesitation marker or planner is a sound or word that participants in a conversation use to signal that they are pausing to think but are not finished speaking. (These are not to be confused with placeholder names, such as thingamajig, whatchamacallit, whosawhatsa and whats'isface, which refer to objects or people whose names are temporarily forgotten, irrelevant, or unknown.) Fillers fall into the category of formulaic language, and different languages have different characteristic filler sounds. The term filler also has a separate use in the syntactic description of wh-movement constructions.