The terms are not exactly equivalent, although both likely hold in this context.
To work in the time domain is (broadly) to consider a signal's strength as it changes as a function of varying time (as opposed to varying frequency, for example). Parametrizing a signal in terms of e^jwt means working in the time domain because one can plug in the time t (in addition to the signal frequency w and probably a prefactor as well) and obtain the signal amplitude.
The phrase of interest, however, refers to a time convention. This is not a field-specific term but refers simply to the convention used to express the signal as a function of time. Here, the complex exponential form is used, where j is the imaginary number. Another option is the sinusoid form, with the two being related through Euler's identity (see also here). Does this make sense?