Numbered group

Words related to a group of a particular number of things or people (solo, duo, trio; alone, in threes).

• What words refer to a group of a particular number?
  single duo duet trio quartet quintet sextet twins triplets quadruplets quintuplets sextuplets twosome threesome foursome fortnight decade century millennium dozen score gross
• What words indicate that only one person does something?
  alone (adv) solo
• What words refer to a group of two?
  pair couple couplet brace dichotomy deuce dual dyad twain yoke
• What words refer to a group of three?
  trilogy trinity triple triumvirate triune
• What words indicate that something is done in groups of a certain number?
  singly one by one two by two three by three by ones by twos by threes in pairs in threes one at a time two at a time three at a time
• What words indicate that everyone is to get a certain number of something?
  one apiece two apiece three apiece one each two each three each