Englishfor English speakers
a
Determinative
—
A is used when the following word could be any of a certain type.
Compare "A book I saw on the shelf" and "The book I gave you yesterday".
a
Noun
—
A is the first letter of the alphabet.
The letter "a" comes before "b".
—
In some schools, an A is a very high grade.
Ron got an A on his earth science test.
costa
—
noun
a riblike part of a plant or animal (such as a middle rib of a leaf or a thickened vein of an insect wing)
—
noun
(= rib)
any of the 12 pairs of curved arches of bone extending from the spine to or toward the sternum in humans (and similar bones in most vertebrates)
DE
—
noun
(= Delaware)
a Mid-Atlantic state; one of the original 13 colonies