| ASTHENOSPHERES | • asthenospheres n. Plural of asthenosphere. • ASTHENOSPHERE n. the upper layer of the earth's mantle, below the lithosphere, characterized by a relatively low resistance to plastic flow. |
| ASTHENOSPHERIC | • asthenospheric adj. (Geology) Of, pertaining to, or arising from the asthenosphere, the soft area of the upper mantle. • ASTHENOSPHERIC adj. relating to the asthenosphere. |
| ASTIGMATICALLY | • astigmatically adv. In an astigmatic manner; through or in relation to astigmatism. • ASTIGMATIC adv. affected with, or pertaining to, astigmatism. |
| ASTRAPOPHOBIAS | • ASTRAPOPHOBIA n. a morbid fear of thunder and lightning, also ASTRAPHOBIA, ASTROPHOBIA. |
| ASTROBIOLOGIES | • ASTROBIOLOGY n. exobiology. |
| ASTROBIOLOGIST | • astrobiologist n. A biologist whose speciality is astrobiology. • ASTROBIOLOGIST n. one who studies astrobiology. |
| ASTROCHEMISTRY | • astrochemistry n. (Chemistry, astronomy) The study of the chemical composition of stars and outer space. • ASTROCHEMISTRY n. the study of molecules and radicals in outer space. |
| ASTROCOMPASSES | • astrocompasses n. Plural of astrocompass. • ASTROCOMPASS n. a navigational instrument for giving directional bearings from the centre of the earth to a particular star. |
| ASTROGEOLOGIES | • ASTROGEOLOGY n. the study of extraterrestrial geology. |
| ASTROGEOLOGIST | • astrogeologist n. One who studies astrogeology. • ASTROGEOLOGIST n. a specialist in astrogeology. |
| ASTROLOGICALLY | • astrologically adv. In an astrological manner. • astrologically adv. With regard to astrology. • ASTROLOGICAL adv. relating to astrology, also ASTROLOGIC. |
| ASTRONAVIGATOR | • astronavigator n. One who performs astronavigation; an astronaut or space pilot. • ASTRONAVIGATOR n. one who practises astronavigation. |
| ASTRONOMICALLY | • astronomically adv. (Not comparable) Of or relating to astronomy. • astronomically adv. (Comparable, degree) In the extreme, very (typically very large). • ASTRONOMICAL adv. related to astronomy, also ASTRONOMIC. |
| ASTROPHYSICIST | • astrophysicist n. One who studies astrophysics. • ASTROPHYSICIST n. a student of astrophysics. |