planetary

Etymology

It is partly borrowed from Middle French planétaire (“of or relating to the planets”), recorded from 1553, and partly borrowed from Late Latin planetarius, which is recorded only as a noun meaning "astrologer", from about 400 in Augustine.^[2][3][4] The Latin word is formed from planēta (“planet”) and the suffix -ārius;^[2][5] the OED notes that the expected Latin adjective would have been planētāris, and Merriam-Webster assumes a Late Latin adjective planetarius behind the noun.^[2][6] Etymonline takes the English word as formed from planet and -ary, perhaps on the Latin model,^[4] and Johnson derived it from the French.^[7] Planēta comes from Ancient Greek πλανήτης (planḗtēs), from the Greek phrase for the "wandering stars".^[4] The OED compares Italian planetario, recorded from 1521.^[2]

Earliest recorded meaning

Of, relating to or belonging to a planet or planets, or moving like one: 1582, in R. Stanyhurst's translation of the first four books of Virgil's Aeneid.^[2] Etymonline dates the word to the 1590s and Merriam-Webster to 1593.^[4][6]

Semantic evolution

Much of the early use was astrological: from 1614 the word meant caused by a planet, or relating to a planet's supposed influence over people and events.^[2] Johnson (1755) listed "pertaining to the planets", "under the denomination of any particular planet", "produced by the planets", with Shakespeare's "planetary plague" in Timon of Athens, and "having the nature of a planet; erratick".^[7] The figurative sense "wandering, erratic", recorded from 1607, is now rare.^[2] The noun meant an astrologer or astronomer from 1625 to 1716.^[2] The planetary nebula, named for its shape as seen through a telescope, is recorded from 1785,^[4] and the noun planetary for it from 1903.^[2] From 1831 the word could mean belonging to the earth as a whole, worldwide.^[2] In mechanics it has described a gear whose axis turns around another's since 1904, and the noun a planetary gear since 1941.^[2]

Timeline

• 1582 – of or relating to a planet, in Stanyhurst.^[2]
• 1607 – figurative, wandering, erratic.^[2]
• 1614 – astrology, caused by a planet.^[2]
• 1625 – noun, an astrologer (obsolete by 1716).^[2]
• 1785 – planetary nebula.^[4]
• 1831 – of the earth; worldwide.^[2]
• 1903 – noun, a planetary nebula.^[2]
• 1904 – mechanics, of a gear.^[2]
• 1941 – noun, a planetary gear.^[2]

Meanings

Adjective

1. Of, relating to or belonging to a planet or planets: planetary atmospheres.^[6][8][2]
2. Of or relating to the whole earth; global or terrestrial: a planetary emergency.^[6][8][2]
3. (astrology) Under the influence of a planet, or caused by one.^[8][6][2]
4. Moving like a planet; orbiting, as an electron around a nucleus.^[6][8][2]
5. (mechanics) Of a gear, having an axis that turns around that of another gear, as in an epicyclic train.^[8][2]
6. (now rare) Wandering or erratic.^[8][6][2]

Noun

1. A planetary nebula.^[6][2]
2. A planetary gear, or a train of planetary gears.^[8][2]

Word family

• interplanetary
• extraplanetary
• nonplanetary
• transplanetary
• planetary science
• planetary nebula

Related words

• planet
• planetarium

References

1. ^ a b c Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z 27 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
4. ^ a b c d e f Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
6. ^ a b c d e f g h Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ a b Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
8. ^ a b c d e f g Collins English Dictionary (2023), Glasgow: HarperCollins