Oftentimes means frequently or often. It's a slightly more formal way of saying “often,” though the two words mean exactly the same thing. You might write that Thomas Edison oftentimes worked through the night on his inventions, or that a dedicated pianist oftentimes practices for hours each day.

The word appears more in writing than in everyday speech. If you're telling a friend about your week, you'd probably say “I often ride my bike to school.” But in a book or essay, you might read “Students oftentimes learn best through hands-on experience.”

Notice that oftentimes is a single word, not two separate words. Some people also use the shorter form “ofttimes,” though that sounds even more old-fashioned. All three versions (often, oftentimes, ofttimes) work perfectly well, so choose whichever fits the tone of your writing or matches how people around you speak.