In the Oxford Advanced Learner's Dictionary, available for you to use at the Writing Center, nouns are designated countable or uncountable according to the following:

In the Oxford dictionary, nouns are countable unless they are designated by the letter [u]. If a noun can be either countable or uncountable (with different definitions, as in the examples given above), then the uncountable definitions are preceded by [u], and the countable definitions are preceded by [c], as in the following example.

ad.ven.ture n 1 [c] a strange or unusual happening (The explorer told the boys about his adventures in the Arctic). 2 [u] risk; danger (Robin Hood lived a life of adventure).