dobson

N ตัวอ่อน ของ แมลง  dobsonfly hellgrammite

DOBSON

DOBSON Dob "son, n. (Zoöl.)

dobsonfly

dob son fly |ˈdäbsənˌflī ˈdɑbsənflaɪ | ▶noun ( pl. dobsonflies ) a large gray North American winged insect related to the alderflies. Its predatory aquatic larva (the hellgrammite ) is often used as fishing bait. [Family Corydalidae, order Neuroptera: several genera and species, in particular Corydalus cornutus. ] ORIGIN early 20th cent.: of unknown origin.

Dobsonian

Dob so ni an |däbˈsōnēən dɑbˈsoʊniən | ▶adjective relating to or denoting a low-cost Newtonian reflecting telescope with large aperture and short focal length, or the simple altazimuth mount used for it. ORIGIN late 20th cent.: from the name of John Dobson, American amateur astronomer, + -ian .

Dobson unit

Dob son u nit |ˈdäbsən ˈdɑbsən ˌjunɪt |(abbr.: DU ) ▶noun a unit of measurement for the total amount of ozone in the atmosphere above a point on the earth's surface, one Dobson unit being equivalent to a layer of pure ozone 0.01 mm thick at standard temperature and pressure. ORIGIN 1980s: from the name of G. M. B. Dobson (1889 –1976 ), British meteorologist.

dobsonfly

dobsonfly |ˈdɒbs (ə )nflʌɪ | ▶noun ( pl. dobsonflies ) a large grey North American winged insect related to the alderflies. Its predatory aquatic larva (the hellgrammite ) is often used as fishing bait. ●Family Corydalidae, order Neuroptera: several genera and species, in particular Corydalis cornutus. ORIGIN early 20th cent.: of unknown origin.

Dobsonian

Dobsonian |dɒbˈsəʊnɪən | ▶adjective relating to or denoting a low-cost Newtonian reflecting telescope with large aperture and short focal length, or the simple altazimuth mount used for it. ORIGIN 1980s: from the name of John Dobson, American amateur astronomer, + -ian .

Dobson unit

Dobson unit (abbrev.: DU ) ▶noun a unit of measurement for the total amount of ozone in the atmosphere above a point on the earth's surface, one Dobson unit being equivalent to a layer of pure ozone 0.01 mm thick at standard temperature and pressure. ORIGIN 1980s: from the name of G. M. B. Dobson (1889 –1976 ), British meteorologist.