diameter English · revision 7962

+ {{infobox|confidence=established|formation=borrowing|attested=before 1387|origins=grc διάμετρος}}

+

+ ==Pronunciation==

+ * IPA: UK /daɪˈæm.ɪ.tə/, US /daɪˈæm.ə.t̬ɚ/^(Roach et al. 2011)

+

+ ==Etymology==

+ It is Middle English diametre, [[bor|fro|diametre]],^(Etymonline)^(Barnhart 1988)^(MWU 2024) from Latin [[m|la|diametrus]], from Greek [[m|grc|διάμετρος|tr=diámetros|t=diagonal of a circle or parallelogram]], short for diámetros grammḗ, the line measuring across,^(Etymonline)^(Barnhart 1988)^(NODE 1998) from diá, across (see [[dia-]]), and [[m|grc|μέτρον|tr=métron|t=measure]],^(Etymonline)^(Barnhart 1988) from PIE [[ine-pro|*meh₁-|alt=*me-|t=to measure]].^(Etymonline)

+

+ ==Earliest recorded meaning==

+ A straight line through the centre of a circle or sphere: before 1387, in Trevisa's translation of Higden's ''Polychronicon''.^(Barnhart 1988)^(OED 1989)

+

+ ==Semantic evolution==

+ A line passing through the centre of any body is from 1387,^(OED 1989) and the transverse measurement or thickness of a figure from about 1391.^(OED 1989) In arithmetic it meant the square root of the sum of the squares of two factors (1557),^(OED 1989) and in architecture the width of a column at its base as a unit of measure (1604).^(OED 1989) As a measure of the magnifying power of a lens, ''magnified 100 diameters'', it is from 1856.^(OED 1989) ''Diametrical'' is from 1553 and ''diametric'' from 1802.^(Barnhart 1988)

+

+ ==Timeline==

+ * before 1387 – a line through the centre.^(Barnhart 1988)

+ * c. 1391 – the width of a figure.^(OED 1989)

+ * 1553 – diametrical.^(Barnhart 1988)

+ * 1604 – in architecture.^(OED 1989)

+ * 1856 – of magnification.^(OED 1989)

+

+ ==Modern meaning==

+ ===Noun===

+ # A straight line passing through the centre of a [[circle]] or [[sphere]] from one side to the other, or its length.^(AHD)^(Collins 2023)

+ # The thickness or width of something round.^(AHD)^(Collins 2023)

+

+ ==Word family==

+ * [[diametral]]

+

+ ==Related words==

+ * [[diametric]]

+ * [[semidiameter]]

+ * [[diametrical]]

+ * [[diametrically]]

+ * [[radius]]

+ * [[meter]]

+

+ ==References==

+ {{reflist}}