The Trinity is a term used to describe God. I found the following excerpt on www.vatican which may help to start your enquiry.
252 TheChurch uses (I) the term "substance" (rendered also at times by
"essence" or "nature") to designate the divine being in its unity, (II) the term
"person" or "hypostasis" to designate the Father, Son and Holy Spirit in the
real distinction among them, and (III) the term "relation" to designate the fact
that their distinction lies in the relationship of each to the others.
You may then need to use this forum to look up each term individually.
This may be in part a language question, and we'll all be happy to help you with that part, but it's also a theological question. You may need a site on Christian theology to understand fully what this concept is about.
thank you Egmont i am very happy to see the answer of my question by Franco-filly.infact i am a in a profession of translation and already had some idea abut it but needed some more detail in an easy way actually when v ask from religious experts it sometime becomes difficult to understand and then become more difficult to explain it in some other language during translation.so that i put my question here that may be i can get answer from someone in the easy words and yeah i have got the the answer in a very easy and clear way.thank you all.hope u will help me further too.