Is there a difference between crows and ravens?

Some crows are ravens.

Ravens and crows share a genus (Corvus), but there are many species within that genus, of which some are ravens. The ravens are the big ones. (They have larger beaks, commensurate with their increased bulk.)

Corvus means raven in Latin. Also, interesting to note is that crows move in groups called "murders" as in "a murder of crows." Similar to a "pride of lions" or a "gaggle of geese."

From Wikipedia:

Raven is the common name given to the largest species of birds in the genus Corvus. Corvids are also commonly referred to as 'crows' and other species in the same genus include jackdaws, and rooks.

Also from Wikipedia:

The true crows are large passerine birds that comprise the genus Corvus. Ranging in size from the relatively small pigeon-sized jackdaws (Eurasian and Daurian) to the Common Raven of the Holarctic region and Thick-billed Raven of the highlands of Ethiopia, the 40 or so members of this genus occur on all temperate continents (except South America) and several offshore and oceanic islands (including Hawai‘i).

Ravens tend to live in mountains. I live in New England and there are crows all over the place but to see Ravens you have to go to the higher peaks in the White Mountains in New Hampshire. Though I have seen ravens in winter in hilly wilderness type areas.

Ravens fly differently. They will soar on wind currents like hawks.

Since it is hard to judge they size of a bird flying some distance you can tell them apart by the shape of their tail.

The ravens tail is diamond shaped.

A crows tail is fan shaped.

Both crows and ravens have a varied diet, They both will eat grain, fruit and beeries and feed on dead animals,

But ravens will also catch insect, small rodents, frogs, and lizards. and small snakes.

I looked in reference and it said a crow was a blackbird. It didn't mention the raven. I then looked up raven and it said that it was a large bird having a black plumage and a croaking call and no mention of the crow.

Look it up for youself and make sure.

Ravens have larger beaks

Quoth the raven "Nevermore."

I don't think the crow ever said anything.

Ravens are classified as predatory birds as they will raid the nests of smaller bird species and take the young as prey. As predatory birds they are protected by federal law.