Computer science is a part of Bioinformatics, but Bioinformatics is not computer science.
Bioinformatics: the collection, classification, storage, and analysis of biochemical and biological information using computers especially as applied in molecular genetics and genomics (source: www.dictionary.com)
A useful source to look up computer related terminologies: www.webopedia.co
In our courses one uses all these words with the same definition considering we must be good in informatics, computer science and bio-informatics in general.