An Etymological Dictionary of Astronomy and Astrophysics

A → rock formed by the solidification of molten material that originated within the Earth (as → magma or → lava).

Etymology (EN): Igneous, from L. igneus “of fire, fiery,” from ignis “fire,” from PIE *egni- (cf. Skt. agni- “fire, sacrificial fire,” O.C.S. ogni, Lith. ugnis “fire”); → rock.

Etymology (PE): Sang “stone, rock,” → stone; âzarin “fiery,” from âzar, variants âtaš, taš, from Mid.Pers. âtaxš, âtur “fire;” Av. ātar-, āθr- “fire,” singular nominative ātarš-; O.Pers. ātar- “fire;” Av. āθaurvan- “fire priest;” Skt. átharvan- “fire priest;” cf. L. ater “black” (“blackened by fire”); Arm. airem “burns;” Serb. vatra “fire;” PIE base *āter- “fire” + -in adj. suffix.

A → rock formed by the solidification of molten material that originated within the Earth (as → magma or → lava).

Etymology (EN): Igneous, from L. igneus “of fire, fiery,” from ignis “fire,” from PIE *egni- (cf. Skt. agni- “fire, sacrificial fire,” O.C.S. ogni, Lith. ugnis “fire”); → rock.

Etymology (PE): Sang “stone, rock,” → stone; âzarin “fiery,” from âzar, variants âtaš, taš, from Mid.Pers. âtaxš, âtur “fire;” Av. ātar-, āθr- “fire,” singular nominative ātarš-; O.Pers. ātar- “fire;” Av. āθaurvan- “fire priest;” Skt. átharvan- “fire priest;” cf. L. ater “black” (“blackened by fire”); Arm. airem “burns;” Serb. vatra “fire;” PIE base *āter- “fire” + -in adj. suffix.

1. To set on fire.
   
2. To take fire, to begin to burn.

Etymology (EN): From L. ignitus, p.p. of ignire “to set fire,” from ignis “fire, flame, light.”

Etymology (PE): Girândan transitive form of gereftan

“to take, catch” (Mid.Pers. griftan, Av./O.Pers. grab- “to take, seize,” cf.
Skt. grah-, grabh- “to seize, take,” graha “seizing, holding, perceiving,” M.L.G. grabben “to grab,” from P.Gmc. *grab, E. grab “to take or grasp suddenly;” PIE base *ghrebh- “to seize”).

1. To set on fire.
   
2. To take fire, to begin to burn.

Etymology (EN): From L. ignitus, p.p. of ignire “to set fire,” from ignis “fire, flame, light.”

Etymology (PE): Girândan transitive form of gereftan

“to take, catch” (Mid.Pers. griftan, Av./O.Pers. grab- “to take, seize,” cf.
Skt. grah-, grabh- “to seize, take,” graha “seizing, holding, perceiving,” M.L.G. grabben “to grab,” from P.Gmc. *grab, E. grab “to take or grasp suddenly;” PIE base *ghrebh- “to seize”).

1. The act or fact of igniting; state of being ignited.
   
2. The process of setting something on fire.

See also: Verbal noun of → ignite.

1. The act or fact of igniting; state of being ignited.
   
2. The process of setting something on fire.

See also: Verbal noun of → ignite.

The minimum temperature to which a fuel must be heated in order to initiate self sustained combustion independent of another heat source.

See also: → ignition; → temperature.

The minimum temperature to which a fuel must be heated in order to initiate self sustained combustion independent of another heat source.

See also: → ignition; → temperature.

A → generalized coordinate that does not appear explicitly in the → Lagrangian function. Also called → cyclic coordinate. Ignorable coordinates do not participate in the → Legendre transformation, and
are also absent from the → Hamiltonian function. The generalized → momentum associated with an ignorable coordinate is a → constant of the motion.

See also: → ignore; → coordinate.

A → generalized coordinate that does not appear explicitly in the → Lagrangian function. Also called → cyclic coordinate. Ignorable coordinates do not participate in the → Legendre transformation, and
are also absent from the → Hamiltonian function. The generalized → momentum associated with an ignorable coordinate is a → constant of the motion.

See also: → ignore; → coordinate.

To set aside, e.g. → ignorable coordinate.

Etymology (EN): From Fr. ignorer, from L. ignorare “not to know, disregard,” from ignarus “not knowing, unaware,” from in- “not,”
→ un-, + gnarus “aware, acquainted with,” related to gnoscere “to → know”.

Etymology (PE): Nâdidé engâštan literally “supposed not seen,” from nâdidé “not seen” (from nâ- “not,” → un- + didé “seen,” p.p. of didan “to see,” → sight) + engâštan “to suppose” (→ hypothesis).

To set aside, e.g. → ignorable coordinate.

Etymology (EN): From Fr. ignorer, from L. ignorare “not to know, disregard,” from ignarus “not knowing, unaware,” from in- “not,”
→ un-, + gnarus “aware, acquainted with,” related to gnoscere “to → know”.

Etymology (PE): Nâdidé engâštan literally “supposed not seen,” from nâdidé “not seen” (from nâ- “not,” → un- + didé “seen,” p.p. of didan “to see,” → sight) + engâštan “to suppose” (→ hypothesis).