Morphology is the study of how things are put together, like the make-up of animals and plants, or the branch of linguistics that studies the structure of words.
In morphology, the word part morph- means "form" and -ology means "the study of." So, those who study how something is made or formed are engaged in morphology. In biology, the morphology of fish might investigate how the gills work as part of the respiratory system. In language morphology, you might study how prefixes and suffixes added to a word change its meaning.