Morphology

What does morphology refer to in Linguistics?

Mariana,

R. L. Trask's A Dictionary of Grammatical Terms in Linguisticsdefines it as:
"The branch of grammar daling with the analysisi of word structure, conventionally divided into derivational morphology (the study of word formation) and inflectional morphology (the study of the variation in form of single lexical items for grammatical purposes).
Hope it helps,
Vero
PS: Here's a pretty nice e-glossary on linguistic terminology that you might find useful. It is fairly specialized, so you will find entries for the different types of morphology as opposed to under "morphology"

very basically, morphology is the study of word formation, of which there are two large categories:

inflectional differences that produce different words from the same combination of letters

and

formation of words related to another single word