boulder

Etymology

It is shortened from boulder-stone,^[2][3][4][5] inherited from Middle English bulder, short for bulder ston.^[6][7][8] The Middle English compound is generally taken to be of Scandinavian origin,^{[9][10][4][8]} and is compared with Swedish bullersten (“a large stone in a stream”), a dialect word of East Gothland,^[2][7][10] made of buller (“noise, rumbling”) (from Old Swedish bulder), bullra (“to roar, rumble”), and sten (“stone”):^[8][7][2] a stone that makes the water roar around it, as opposed to klappersten, a smaller pebble.^[2][11] The OED notes that no matching word is known elsewhere in Swedish, Icelandic, Norwegian or Danish, so the relationship is uncertain.^[2] Etymonline also suggests that the first element may come from a word for a round object, ultimately from Proto-Indo-European *bʰel- (“to blow, swell”),^[12][9] while Partridge and Merriam-Webster compare Danish buldre (“to roar”).^[13][8][14]

Earliest recorded meaning

A stone worn round, a cobblestone: the compound bulder ston is used about 1300 in Havelok the Dane, of a stone thrown against a door.^[6][7][2] The word on its own is recorded in 1421, in the York Minster fabric rolls, of stones bought for paving,^[6][7] and in the modern form from 1607, in Markham's Cavelarice, for a rounded water-worn stone larger than a pebble, used for paving and building.^[2]

Semantic evolution

The word at first meant a cobble, a rounded stone of medium size.^[2][12] Ayto notes that it appears on its own, outside the compound, only in the 17th century.^[5] The geological sense, a large weathered block of stone carried away from its parent rock, is from 1813 in Etymonline and 1815 in the OED;^[12][2] from it came boulder clay, clay with many boulders left by melting glaciers.^[3] From 1861 the word was also used of a lump of other material, in mining of a large piece of ore found away from the lode.^[2] In geology a boulder is now a rock fragment larger than a cobble.^[15] The verb, to make into boulders, is recorded from 1839,^[2] and in American slang a boulder was a diamond (1899) and later crack cocaine.^[16] In East Anglia a separate dialect word boulder meant the bulrush.^[17][2]

Timeline

• c. 1300 – bulder ston, a rounded stone.^[6][7][2]
• 1421 – bulder, a cobblestone.^[6][7]
• 1607 – boulder, a water-worn rounded stone.^[2]
• 1815 – in geology, a large weathered block of stone.^[2]
• 1839 – verb, to make into boulders.^[2]
• 1861 – a lump of material; in mining, a detached piece of ore.^[2]
• 1899 – in American slang, a diamond.^[16]

Modern meaning

Noun

1. A large rounded mass of rock, worn smooth by erosion and often moved from its place by water or ice: A boulder had rolled onto the mountain road.
2. (geology) A rock fragment larger than a cobble, more than 256 millimetres across.

Verb

1. To climb large boulders.

Word family

• bouldered
• bouldery
• bouldering

Related words

• boulder clay
• bulrush

References

1. ^ a b 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 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
4. ^ a b Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
5. ^ a b Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
6. ^ a b c d e Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
7. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
8. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
9. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
10. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
11. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
12. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
13. ^ Partridge, Eric (1966), Origins: A Short Etymological Dictionary of Modern English, 4th ed., London: Routledge & Kegan Paul
14. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
15. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
16. ^ a b Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com
17. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)