a glass of water

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.

glass Noun

— Glass is a transparent solid and is usually clear. Windows and eyeglasses are made from it, as well as drinking glasses. Through the window glass I could see the trees bend in the wind, but I was warm indoors. — A glass is a drinking cup with no handle. As soon as I finished drinking, he filled up my glass again.

of Preposition

— Made using. It is a house of cards.

water Noun

— Water is a clear liquid of the chemical compound Hsub2/subO that all living things need in order to live. The dog drank the water from his dish Can I please have a glass of water? Your plant needs more water as it is about to die. — A water is a bottle or glass serving of water. "I want to order two waters, waiter". — Water is mineral water. — Water is one of the four basic elements. — Water is urine. — Water is amniotic fluid. Right before the woman went into labor, her water broke.

water Verb

— If you water something, you add water to soil around plants. He waters the plants. — If you water something, you give water to animals. He waters the horses. — If you water something, you dilute it. — If something waters, it fills with water; it secretes water. His eyes watered as he cut up the onion.