quaternary

From the Latin quaternārius (“containing or consisting of four”), from quaternī (“four each”, “four at a time”) + -ārius (whence the English suffix -ary); compare the French quaternaire.

• (UK) IPA^(key): /kwəˈtɜːnəɹi/; (rare) IPA^(key): /ˈkwɔːtən(ə)ɹi/
• (US) IPA^(key): /ˈkwɑːtɚˌnɛəɹi/

  • Audio (US)

    (file)

• Audio (AU)

  (file)

quaternary (not comparable)

1. Of fourth rank or order

   the quaternary stress in a pronounced word

2. Of a mathematical expression containing e.g. x⁴
3. Relating to or in number base four
4. (organic chemistry) quaternary ammonium

The etymologically correct fourth ordinal from Latin (following tertiary) is quartary, but quaternary (from the distributive number instead) is common, particularly in biology.

• quaternion

• bisquaternary
• quaternary ammonium

• unary, unitary (1)
  • primary (1st)
• binary (2)
  • secondary (2nd)
• ternary or trinary (3)
  • tertiary (3rd)
• quaternary (4)
  • quartary (4th)
  • tetranary (4)
• quinary (5)
• senary (6)
• septenary (7)
• octonary (8)
• novenary (9)
  • nonary (9th)
• denary (10)
• duodenary (12)
• vicenary (20)
• tricenary (30)
• sexagenary (60)
• centenary (100)

quaternary (plural quaternaries)

1. (chemistry) A quaternary compound.
2. (geology) The Quaternary period or the system of deposits laid down during it.