Let’s break it down.
The ABC of LGBT – and I:
Lesbian is used to describe a woman who is attracted to other women.
Gay is used to describe someone who is attracted to someone of the same sex.
Bisexual is used to describe someone who can be attracted to men and women.
Transgender is used to describe someone who sense of their own gender does not match the sex they were assigned at birth.
Intersex refers to someone who is born with sexual anatomy, reproductive organs, and/or chromosome patterns that do not fit the typical definition of male or female.
To note: while LGBT is increasingly understood and used in different regions on the world, in many countries other terms may be preferred.