Meatus is the singular. The plural form - which can hardly be necessary - would be meatus ( pronounced with a long last syllable "may-ya-TOOCE") in Latin, or simply meatuses.
The plural of meatus is meatuses or meatus - both forms are accepted.
The singular form of the demonstrative pronoun 'these' is this.
The singular form of "that" is "it."
A meatus is a tubular opening or passage in the body.
The singular form is cuff.
it is already in its singular form.
"Stratum" is the singular form of stratum. The plural form is "strata".
The external auditory meatus and the external acoustic meatus are two names for the same structure.
The form hypothesis is the singular form. The plural form is hypotheses.
A singular form of dice is a die
The singular form of feet is foot.
The singular form of Oases is, Oasis.