आदि

आदि = अ द इ
up to give inward
up to roll inward = till where the wave reaches - tide mark
up to object(give)
up to object(roll)

comment
I believe आदि अन्त are to be interpreted as वर्ण समास and not as पद.
These are to be interepteed in context of तिङ् activities. आदि is when you start the activity of launching boat in waters and अन्त is when/where the activity ends.