Dot
From www.oscarvandillen.com
Definition
A dot (literally: a point) is a symbol in notation to lengthen the duration of a note by half, by 50%. A second dot will add half of half, a quarter - a third, half of half of half: an eighth, and so on.
More than one dot
Thus there can be more than one dot at a notehead, lengthening a note almost in comparison to the Paradox of Zeno: a note with a series of dots will come close to approaching its double duration, yet never completely reaching it.
