[9mm_fan]

Thiru Neduncheziyan avargale!!

Vanakkam. The word "thaLapathi" is derived as follows:

The root is thaL, which means that which is at the base and increased in size or in other ways.

thaL > thaaL - foot, feet, base.
"eNkuNaththaan thaaLai vaNangkaath thalai" (kuraL).
"thaaLunda niiraith thaalayaale than tharuthalaal" (Avvai).
thaaL > thaaLam: beats as synchronised by the movement of the feet; now, generally, any beat of drum or as measured by the movement of hands.
thaL > thaLam : base, something like feet, from which all movement takes place. Organisational base.
thaLam + pathi = thaLapathi. (the leader of a base; a base commander.)

pathi-thal: pathinthu iruththal. ( entrenched or well secured in a place. ) (other meanings are not relevant here at this moment).
pathi = a ruler or official or commander, entrenched or well-secured in a place; one who rules the place; a leader.
From the above, "thaLapathi" meaning is clear.