“Checked” has been a term that is reported in various languages, but lacks a clear definition. It usually refers to syllables or vowels that are closed by oral or glottal stops; associated with distinct tones; have glottalized quality; and/or have shorter duration. My study asks: is “checked” a meaningful phonological feature in languages where it is reported? How do “checked” syllables differ from closed syllables? How do “checked” tones differ from glottalized tones? How do “checked” vowels differ from short vowels? And how does “checked” phonation differ from creaky phonation? To answer these questions, I have surveyed Chinese and Zapotecan languages. The focuses of my presentations are 1) how to determine the phonological structure that “checked” feature is assigned to; 2) how to determine whether the glottal stop in Vʔ structure is a segment or a suprasegment; 3) how to determine whether “checked” is a meaningful phonological feature when it is a syllable type vs. when it is a phonation type.