Actions on the blade when defensive are considered parries, and when offensive are considered beats or engagements. For the purposes of this post we’ll just consider how the blade contact is made and not make a strong distinction between parry, beat and other engagements.
In fencing, fencers don’t normally cross their feet when moving. Instead they make sort of shuffle steps where the lead foot stays in the front, and the trailing foot stays behind. Forward steps are sometimes called advances, and backward steps are sometimes called retreats.
Having just watched the most recent foil bouts in the 2020 Olympics, I have reason to believe that some of the examples in this article are now out of date. I think that the basic explanations and reasoning are still accurate, but the timings seem to be a lot tighter now against slow attacks, making it more possible to place a line. I will need to review this with some FIE referees and provide an update.
To a laymen, I think that fencing can seem really daunting. If you look up glossaries of terms, such as the one on wikipedia you’ll find a list of dozens of terms in French, Italian and English pertaining to various ways fencers can move, or their equipment or the rules of the sport etc. Fencer’s tend to really like cryptic terminology and technical definitions – I think it makes us feel smart! But really, it’s not all that complicated.