Terms for effort - EZ, smooth vs technique? Strong vs fast? And what is "stretch?"

Mostly solo swimmer, but try to get in 1X/week with a nearby Masters team.  When I started, I was following the "Basic" workouts, and I often go back and follow those (though they became largely jumbled with the new board).  Those workouts were spelled out pretty clearly, to me at least.  The main set was for a specific event, and they were to be swum at race pace.  Similar to USRPT, but designed to be swum to completion, rather than the normal "until you cant' make the interval" for most USRPT.

Anyway, I try to put things in context of what event I'm swimming when I think about effort level in terms of percent.  Not always perfect, but easier for me to get my hands around.  But then there are often terms, and I find some of them a bit hard to find out exactly what should be faster.  Easy is pretty easy.  But how about smooth vs technique?  Which one is faster, or requires more effort?  Technique seems like the same effort level as easy from what I gather, but more focus on ensuring proper technique.  Is smooth really any different?  Okay, next pair......"Fast" vs "Strong."  Is that like a tempo thing, where maybe "Fast" is like a 50, but "Strong" is like a 200?  That is kind of how I usually approach those, where the strong is a slower tempo, but I pull very hard, whereas fast is turnover.

New one I came across looking at open water workouts......"Stretch."  Anyone know what that is?  Not sure how to contact the author of the coach, back when the workouts were posted as part of the forum, it was great because we could post up questions and actually interact with the coach.