1st_ Fifth letter of the Spanish alphabet, and second vowel. It is used as the conjunction 'and' in cases where the next word begins with the letter /i/ , although there are exceptions such as in interrogations or exclamations. 'e' is the symbol for the so-called "Euler number", after the mathematician Leonhard Euler. See Euler-Lagrange, logarithm, sudoku. In physics 'e' represents the electron and the value of the electric charge. In trade and economics 'e' represents the exchange rate between currencies. 6th_ 'e' is the "estimate sign" used by the European Union on products that comply with the quantity values printed on the package. 'E' is the symbol for 'energy' in physics. 8th_ 'E' is the symbol of the prefix exa- as "a trillion times". 9º_ 'E' represents the cardinal point East. 10º_ 'E' is the musical note mi in Anglo-Saxon notation. See e- , -e .
