|Unicode name||HIRAGANA LETTER SMALL TU|
If ending a word, results in the word ending in a glottal stop.
In no case is it pronounced like the full-size つ (tsu).
Combining form 
- The sokuon: a small form of つ (tsu). In romanization, this is represented by doubling the following consonant. The equivalent in katakana is ッ.
- A glottal stop or “choked sound”.
See also 
- (Hiragana) 平仮名; あぁ, いぃ, うぅゔ, えぇ, おぉ, かゕが, きぎ, くぐ, けゖげ, こご, さざ, しじ, すず, せぜ, そぞ, ただ, ちぢ, つっづ, てで, とど, な, に, ぬ, ね, の, はばぱ, ひびぴ, ふぶぷ, へべぺ, ほぼぽ, ま, み, む, め, も, やゃ, ゆゅ, よょ, ら, り, る, れ, ろ, わゎ, ゐ, ゑ, を, ん, ー, ゝ, ゞ, ゟ
Usage notes 
Primarily used as the sokuon (for gemination), which is a common sound. Used as a glottal stop at the end of interjections, primarily expressions of surprise or effort.