cardinal vowel 
noun Phonetics
Each of a series of vowel sounds used as a standard reference point to assist in the description and classification of vowel sounds in any language.Leave it to the IPA to reserve the usual print glyph for ‘a’ for a cardinal vowel sound that is hardly ever used in any language....
- The primary and secondary cardinal vowels are often referred to by a number as well as by their symbols.
- The links at the bottom of this section are to diagrams of acoustic data plotted onto cardinal vowel charts.
- astatine
- aster
- -aster
- asterisk
- asterism
- astern
- asteroid
- asteroidal
- Asteroidea
- asteroseismological
- asteroseismologist
- asteroseismology
- as/that was
- as the case may be
- as the crow flies
- asthenia
- asthenic
- asthenosphere
- asthenospheric
- (as) thick as a brick
- (as) thick as poundies
- (as) thick as thieves
- (as) thick as two (short) planks (or as a plank)
- (as) thin as a rake
- asthma