I do not understand the difference between conversation (n) and talk (n). I am only interested in the difference in the following definitions:
1: an informal talk involving two people or a small group of people : the act of talking in an informal way
1: an occurrence in which one person talks about something with another person : a conversation or discussion
2: the act of talking about a subject with another person or group : discussion or conversation
Source: Merriam-Webster’s Advanced Learner’s English Dictionary
Some examples to put it into concrete:
- They had a talk/conversation while waiting at the dentist's.
- The conversation/talk got unpleasant.