I have a younger sister.

I Pronoun

— The person who is speaking or writing I am writing this, and you are reading it.

I Noun

— The ninth letter or the alphabet; previous H, next J. I is a vowel.

I Symbol

— A symbol meaning first, as in "George I" (which is said as "George the first"). — The symbol for iodine on the periodic table of elements. — The symbol for electrical current.

I Number

— This is the roman numeral for one (1). It may be written as I or i.

i Noun

— The ninth letter or the alphabet; previous H, next J. I is a vowel.

have Verb

— Someone has something if the thing is in their hands. The person is holding or gripping it. Do you have a spoon, or do you need me to give you one so you can eat the soup? — If you have uto/u do something, you must do it. I have to go. I had to do it. — Someone has something if the thing is that person's thing: the person owns it; it belongs to the person. The rich family has a big house. — If you have you hold something in the mind. I have a doubt about him. — If you have you join something. We have lunch at 13:00. — You use have to say that you suffer from something or to tell the experience. I have a defective vision. (I don't see well.) He had a wonderful time with his friends.

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.

younger

— adjective (= jr.) used of the younger of two persons of the same name especially used to distinguish a son from his father John Junior John Smith, Jr.

sister Noun

— Your sister is the daughter of your mother and father. My parents have three children: me, my brother, and my sister. — A sister is a nurse in a hospital. The Sister said that I must rest more.