You also learned a little bit about cis-trans isomerism and learned a few important reactions of alkenes and alkynes such as hydrogenation, halogenation, and polymerization.
Then, a little chemistry knocked the acid off, creating what was clearly an alkene, so they named it benzene, because it was an alkene that was from the benzoin resin.
So three words representing three different groups of organic compounds: alkanes for all single bonds, alkenes if they contain double bonds, and alkynes if they contain one or more triple bonds.
That may not sound like a big deal at first, but alkenes and alkynes don't have that kind of freedom, and that simple fact has a huge affect on their properties.
Just to note to avoid confusion: polyethylene has that " -ene" sound in it, right, but it's not an alkene because all those double bonds get broken to form new sigma bonds.
If you paid attention, you learned that hydrocarbons with double bonds are called alkenes and those with triple bonds are called alkynes and that the naming rules are the same as for alkanes.