What it means
The beginning of words for something that lies or happens between two things. Intercostal muscles lie between the ribs; an intervertebral disc sits between two vertebrae; interstitial fluid is in the spaces between cells. It is easy to mix up with intra-, which means inside: an intramuscular injection goes into a muscle.
Remember it
An interstate highway runs between states; intra- is inside.
Related terms
intramuscular
Into a muscle; used for a drug given by injection into muscle tissue.
trans-
A word beginning that means across, through or beyond.