The origins of lambaste are somewhat uncertain, but the word was most likely formed by combining the verbs lam and baste, both of which mean to beat severely. (Incidentally, lambaste can also be spelled lambast, despite the modern spelling of the verb baste.) Some other synonyms of lambaste include pummel, thrash, and pound.
According to the Wikipedia article on Fahrenheit: Fahrenheit remains the official scale for the following countries: the Bahamas, Belize, the Cayman Islands, Palau and the United States and associated territories (Puerto Rico, Guam and the U.S. Virgin Islands). Canada retains it as a supplementary scale that can be used alongside Celsius.
The use of the phrase pound sign to refer to this symbol is found from 1932 in U.S. usage. Before this time, and still outside the U.S., the term pound sign was used to refer to the pound currency symbol (Â£) or the pound weight symbol (lb). An alternative theory is that this name arose from the fact that character encodings used the same code for both the number sign and the British pound sign Â£.