different tests?

What is the difference between a 'pelvic sonogram' and an 'ultrasound'?  Are they not the same test?  If not, do they give the same results or is one more accurate than the other in detecting anything abnormal?  I was told that an ultrasound is preferable for seeing anything unusual on the ovaries, whether it be a cyst or a tumor, and that a sonogram would be most useful for anything in the pelvic area.  But I've had several ultrasounds by my doctor and he can see everything he needs to see (he does this as part of my yearly physical because of my age, 50, so he can see anything suspicious right away).  I'm somewhat confused now if one is better than the other or if it matters.  Thank-you so much for any information you can give.