Great answer Stephen! I would add that these terms are used alot in the memory field and, as Satheesha points out, are generally very poorly defined, so let's get working on it ;)

In signalling, early can be the time before the cell has time to make other proteins, for example cytokines that might induce later effectors.

Thanks

I work on innate immune response in fishes against viral infection. In one of my experiments (in-vivo), observed rapid changes in kinetics of viral genes and host immune genes. I wished to write in my article based on the data to write early infection (3-6h), peak infection (12h - 2 d) and recovery phase (3-7d). That condition may change depending on the host and pathogen, level of infection etc. Therefore, wished to know is there any definition or guidelines to use such terminologies.

All the suggestions have been really helpful.