dual

Pronunciation

• IPA: /ˈdul/, /ˈd(j)u.əl/^[1]

Etymology

It is borrowed from Latin duālis (“containing two”),^[2][3][4] from duo (“two”), from PIE Proto-Indo-European *dwo- (“two”) (see two).^[3][4] Barnhart notes that Latin duālis is thought to be Quintilian's translation of Greek Ancient Greek δυϊκός (duïkós), in the term for the dual number.^[2]

Earliest recorded meaning

In grammar, the form or number denoting two: 1607 in Barnhart and the OED,^[2][5] about 1600 in Etymonline.^[3] MWU has 1597.^[4] As a noun, a name for the two middle incisor teeth, it is late Middle English (1541 in the OED), long obsolete.^[6][5]

Semantic evolution

The general sense, composed of two parts, twofold, is from the 1650s.^[3][5] The noun, the dual number in grammar, is from 1650.^[5] In chess problems a dual is an unintended alternative move by White (1875).^[5][6] A dual carriageway, a road with separate lanes for each direction, is from 1933, and the verb, to make a road into one, from 1959.^[5]

Timeline

• 1541 – the incisor teeth (obsolete).^[5]
• 1607 – the dual number.^[2][5]
• 1654 – twofold, double.^[5][3]
• 1875 – in chess problems.^[5]
• 1933 – dual carriageway.^[5]

Modern meaning

Adjective

1. Made of two parts, often alike or complementary; double.
2. Having a double character or purpose.
3. (grammar) Of a number category denoting two persons or things, as in Greek, Sanskrit and Old English.

Noun

1. (grammar) The dual number, or a word in it.

Word family

• dually
• dualistic
• dualize
• dualism
• duality
• dual-purpose
• dual citizen
• dual citizenship

Related words

• two
• duet
• double

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
3. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b c d e f g h i j k Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
6. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press