Does ～たり～たりする mean "and" or "or" in dictionary definitions?

Question

I think that ～たり～たりする generally means "do things like (among other things)", but in dictionary definitions, can the pattern ～たり～たりする mean "and", "or" or "and/or"?

In e.g. XたりYたりする would it imply that both X and Y occur or can X occur without Y occurring (or vice versa)?

In the Daijisen definition for よく for example, it's used in the following way:

困難なことをしたり、考えられないような喜ばしい結果を得たりして感じ入るさま。

Being impressed by something which takes difficulty (or? and? and/or?) the achievement of an unthinkably delightful outcome.

How would it differ from dictionary form verb+ことや (if "or") and ～て/～で (if "and") etc.?

Answer 1

In the example you cite, the meaning is obviously "or", and I think that is the meaning たり generally has. The the following example implies "and":

飲んだり食べたりした
Denotes: 'drank or ate'
Implies: 'drank and ate'

rather than "or", and that is probably because of pragmatic reason: It is about something that already happened, and if the person did only one of drinking or eating, then there is no reason to mention both, so the very fact that both are mentioned in the sentence implies that both were done.

In your example sentence, it is a definition, which is talking about the possibility of one or another event being done, either case of which satisfies the definition; that is why it remains to mean "or".

Answer 2

や is not used for verbs, and ～て implies that you do one thing after another. ～たり～たりする lists verbs which are done in no particular order, possibly among other things.