Dear
charvi.singh
I can explain you by an example: Transit of Lagna Lord Over Seventh House
Suppose your ascendent (Lagna) is "taurus" - then your lagna lord is "Venus"
and if it is placed in "Gemini" Sign - that means placed in second House.
The above two lines states the position in birth chart (position of planet at the time of birth).
If your ascendent (Lagna) is "taurus" - then your seventh house is "Scorpio" Sign.
when "venus" comes in "Scorpio" sign in current position, then it "TRANSITS" over the seventh house for the above suppposed position.
Note "Venus" is also lord of lagna in "Libra" ascendent (Lagna).
i hope that the above example is sufficient to answer your query.
if still in doubt.
please feel free to write me at
indersonkar@hotmail.com
inder kumar