What does "buy the dip" mean?
You're spot on!
I don't have enormous gobs of cash sitting around (who does?!) but as I get paid monthly I have some sitting ready for bills or going out next week. Buy the Dip - or more bluntly - Buy the F'ing Dip (BTFD) - is a reminder that:

The dip will be temporary
Don't later regret that you didn't buy
Consider buying a dip IF YOU ARE ABLE TO

Interesting commentary from Dr Adam Back talking with Preston Pysh and PlanB on Preston's podcast recently; accepted experience/wisdom was to ignore dips below 20% - that is a &quot;dip&quot; of 10% wasn't even worth the definition of &quot;dip&quot;. Larger dips of 20%+ are therefor worth buying if you're able.
For me, I dollar cost average with a daily buy so I don't really watch the price - some days I get more sats, some days I get less sats, but at the end of every day I have more sats than yesterday.
Over the long term bitcoin will rise in value, and therefore I've protected my savings (future purchasing power). It's that simple. I'm not a trader. I don't have great gobs of cash sitting around. Work in a job and earn living, pay my bills, and save in bitcoin.
Do what you're able. :-)
PS - During the 2017 bull market there were about half a dozen dips of 30%; this dip is the first half decent one so far. aka: this is normal for bitcoin.