Portuguese is an interesting language. Like my native tongues, it has special verbs for having lunch and dinner. Almoçar and jantar, respecitvely.
In smaller towns in Portugal, most restaurants and tascas are closed between the above-mentioned meals. But let's say one is semi-open and you're unsure what to ask for in order to eat around the in-between time of say six in the evening, an hour and a half or so before they officially open for jantar.
And here it's tricky, because you need to carefully avoid asking for an early dinner, jantar. If you do so, you risk being taken for a bife (a beefstake). That's what people call very pale foreigners (usually of English descent), who don't know you need to use sunscreen and become very well done under the sun.
Instead make sure to say you want to almoçar, thus implying that you worked so hard that you didn't even have time to have lunch on time. The sympathetic Portuguese will often offer you something to eat, even if they're on a break.