The Word is:”an”

an

/an,ən/
determiner
determiner: an
the form of the indefinite article (see a1) used before words beginning with a vowel sound.

-an

(ə)n/
suffix
suffix: -an

1.forming adjectives and nouns, especially from:
names of places.
“Cuban”
names of systems.
“Anglican”
names of zoological classes or orders.
“crustacean”
names of founders.
“Lutheran”
2.CHEMISTRY
forming names of organic compounds, chiefly polysaccharides.
“dextran”

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