Definition of "tritten"
Bitte, tritt ein = Please come in
Ich trete zurück = I step back
Er tritt das Pferd = He kicks the horse
What does tritten actually mean?
The verb is treten, which means to step/kick/tread:
- die Kinder treten zur Seite = the children step aside
- sie ist mir auf den Fuß getreten = she stepped on my foot
- er hat eine schwangere Frau in den Bauch getreten = he kicked a pregnant woman in the stomach
- tritt aufs Gaspedal! = step on the gas pedal!
Sometimes it's used in a less literal sense:
- der Fluss tritt über die Ufer = the river bursts its banks
- wir wollen mit euch in Kontakt treten = we want to get in contact with you
Then there are prefixed forms, eintreten which means to step in, and zurücktreten means to step back. They both have many more meanings, for example you can eintreten/kick down a door, or eintreten/enter into politics, but I think that's something you can learn later.
Check the conjugation for treten here: http://www.canoo.net/inflection/treten:V:haben:sein
the infinitive of "tritten" is "treten". it means to kick, to tread.
however, when you add a prefix to it, the meaning of the verb changes. this is the case with many verbs in german. some examples:
vertreten: represent, substitute
zurücktreten: resign, step back
austreten: leave, resign
eintreten: enter, join
betreten: enter, trespass
übertreten: pass over, breach
Please note that the Infinitive is "treten" and none of the forms of the word is "tritten". "Tritten" doesn't exist ;)
Oh, actually it does, it is the dative plural of the word "Tritt" (kick, noun). Then it's written with a capital letter. But the verb treten (to kick) does not have a form that looks like this.
TrioLinguist's answer is very good.
If "Bitte, tritt ein" is translated as "Please, come in", it's a correct but not exactly literal translation. The literal translation would be "Please, step in(side)." So you're back to "step" and "kick".