Staccatissimo
Staccatissimo means as staccato as possible or play the note as short as possible and is shown in musical notation with a small triangle or short line below or above the note ball (depending on the stem direction). 
Staccatissimo is an articulation mark and is entered with the trill menu or the default hotkey <shift Q> found there.
The duration of staccato notes can be adjusted under [Options|Music|Staccatissimo %] and is by default a quarter (25%) of the notated duration.