Markdown rhymes with:
breakdown, crackdown, knockdown, lockdown, shakedown, ashdown, blastdown, breakdown, clampdown, closedown, comedown, countdown, crackdown, drawdown, godown, hillsdown, hoedown, knockdown, lansdowne, letdown, lockdown, lowdown, meltdown, piltdown, putdown, rundown, shakedown, shootdown, showdown, shutdown, slowdown, southdown, sundown, touchdown, turndown, underdown, writedown
Markdown sounds like:
marsden, marsdon, marston, moorestown, morristown