Bastion rhymes with:
sebastian, sebastian, christian, combustion, congestion, digestion, exhaustion, faustian, indigestion, ingestion, mcchristian, question, sebastian, suggestion
Bastion sounds like:
bagdon, baisden, basden, basten, bastian, bastien, bastin, baston, bastone, beaston, becton, begotten, bigtime, biosystem, bogdan, bogden, bogdon, bostian, boston, bostonian, boughten, boughton, boustany, buckstein, bustin, buxton