The traditional mythological creature is the ogre. Orcs are more contemporary and were used by Tolkien in literature (Lord of the Rings), and have since found their way into RP games such as D&D. But ogres and orcs have much in common.
Both are brutish, aggressive, repulsive, malevolent, and nasty creatures. Both characterize evil and represent deadly harm to humans in some way. Both are generally presented as creatures that eat people. Orcs are cannibalistic. In most cases, both are presented as somewhat stupid creatures. There is one clever orc in Tolkien’s stories, but he was still evil.
In the case of Orcs, they often end up as fodder or pawns in battles or doing the bidding of another more intelligent character. They can also be cowardly.
Generally, Ogres, while rightly and properly representing evil, are used or fooled by others and are often tricked into things leading to their own demise, precipitated by their own greed and nastiness. But these creatures are more classic and date back farther in history than orcs.
A note about cartoons and nice little very un-Brothers-Grimmly characters such as Shrek. When these characters are depicted as sweet and not-so-ugly, misunderstood, and mistreated heroes; it is playing with folklore and a silly cartoon. Ogres are bad news, period. No exceptions. A character is an ogre based on behavior and outlook, not skin color, size, or birthright. I like Shrek, but he is no ogre, regardless of what the Hollywood script says.
To further jump the fence to human mischaracterization, peeps are often metaphorically referred to as ogres. This is not because they look like ogres (some may). It’s because they are considered by someone as bad people based upon their behavior. There are no good orcs or ogres. If they are good, behave well, and hold some moral high ground, then they are something other then an orc or ogre. Evil is what they do, and that defines what they are.
Remember: Scorpions sting frogs. Frogs that can be persuaded otherwise drown. If you don’t know that story, click here.
Look both ways for any harm coming your way.
Avoid doers of evil and mind your own gaps.