What is a
Memo as referred to in transaction between a technology firm and Investment bank? Does
Memo has any legal validity in Courts of Law. For example as Memo refereed to in this case between Dragon and Goldman Sachs.
Memmo referred to in the article is "memorandum", basically - a letter.
Memo as a separate field in the transaction report is a "free-text" field in which you can put the description of the transaction, reference, account number, or whatever else, similar to the "memo" field on checks (at least in the US, not in every country the have such a field).
I'm not a lawyer, but I would expect it to have some legal validity as a supporting evidence of intention, if the transaction is later contested. In absence of any other proof you can claim that you paid for what you mentioned in the memo (for example if you put there the invoice number), if the seller claims that you paid for something else.