Callender rhymes with:
challender, blender, challender, lender, schlender, slender, splendor, bender, blender, brender, brendor, cavender, challender, contender, defender, ender, engender, fender, gender, kender, lender, offender, pender, pretender, render, schlender, sender, skender, slender, spender, splendor, stender, surrender, suspender, tender, transgender, vendor, wender, yender, zehnder, zender
Callender sounds like:
calamander, calandra, calandro, calendar, callander, challender, cilantro, colander, collender, cylinder