else

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Other; different.
• adjective Additional; more.
• adverb In a different or additional time, place, or manner.
• idiom (or else) Used to indicate an alternative.
• idiom (or else) Used to indicate negative consequences that will result if an action is not followed.
• idiom (or else) Used after a command or demand to make a threat:

from The Century Dictionary.

• In another or a different manner; in some other way; to a different purpose; otherwise.
• In another or a different case; if the fact were different; otherwise.
• Besides; other than the person, thing, place, etc., mentioned: after an interrogative or indefinite pronoun, pronominal adjective, or adverb (who, what, where, etc., anybody, anything, somebody, something, nobody, nothing, all, little, etc.), as a quasi-adjective, equivalent to other: as, who else is coming? what else shall give you? do you expect anything else?
• [The phrases anybody else, somebody else, nobody else, etc., have a unitary meaning, as if one word, and properly take a possessive case (with the suffix at the end of the phrase): as, this is somebody else's hat; nobody else's children act so.]

from the GNU version of the Collaborative International Dictionary of English.

• adjective Other; one or something beside
• adverb Besides; except that mentioned; in addition
• adverb Otherwise; in the other, or the contrary, case; if the facts were different.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Other; in addition to previously mentioned items.
• adverb Otherwise, if not.
• conjunction For otherwise; or else.
• conjunction computing but if the condition of the previous if clause is false, do the following.