question..is hedging the same as margin loans, page-5

Hey Bionic,
Whilst you are around...

Can you tell me what this trading 'jargon' means ...
in relation to the case in US about hedging and beneficial ownership etc.

http://www.mwe.com/index.cfm/fuseaction/publications.nldetail/object_id/20b0b158-b27d-47bd-91ae-2279415b3cc5.cfm

"As a result of the incorporation of the Regulation 13D-G definition of beneficial ownership into other contexts, additional consequences may follow from a holding that TRS long parties hold beneficial ownership. Among those consequences could be the triggering of state takeover statutory provisions, poison pills and other corporate charter, bylaw and contractual provisions. Indeed, some poison pills have already been adopted that include derivative economic holdings in the calculation of kinds of “ownership” that trigger the pill."

What's a 'Poison Pill' in the sharetrading context?