That is a good question. I can see your confusion, since many people do not use this word anymore. It has sort of fallen out of our vocabulary, but a few generations ago, declamations were an important part of society. Basically declamation is the art of public speaking. It is sometimes called, oratory. In terms of kinds of declamations, there are both fuzzy borders and differences based upon time period and place. For example, if you were in the Greek and Roman worlds, there were funeral orations, panegyrics, invectives, persuasive speeches and more. Some famous orators are: Demosthenes and Cicero. In our day, the categories are different. Usually speeches are found in political and religious contexts.