2003 Honda Accord 4 cylinder timing belt

Exactly.

As with so many issues, the Owner’s Manual and/or the Maintenance Schedule will prove to be the ultimate source of information on this point. If you have a timing belt, its replacement will be listed at a specific mileage (60k? 90k? 105k?). If replacement of a timing belt is not mentioned anywhere, that is your best indication that this engine has a timing chain.