frank

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

• noun A frankfurter.
• adjective Open and sincere in expression; straightforward.
• adjective Clearly manifest; evident.
• transitive verb To put an official mark on (a piece of mail) so that it can be sent free of charge.
• transitive verb To send (mail) free of charge.
• transitive verb To place a stamp or mark on (a piece of mail) to show the payment of postage.
• transitive verb To enable (a person) to come and go freely.
• noun A mark or signature placed on a piece of mail to indicate the right to send it free of charge.
• noun The right to send mail free.
• noun A franked piece of mail.

from The Century Dictionary.

• noun A member of a body of Germanic tribes which coalesced under this name in the third century, and afterward separated into three groups, the Chatti, the Ripuarian Franks, and the Salian or Salic Franks.
• noun [A readoption of the Oriental form of the European name Frank, originating at the time of the crusades, when the Franks that is, the French, and by extension the other nations of western Europe) became familiar to the Turks, Arabs, etc. See Feringee.] A European of the western nations: a common designation among the Turks, Arabs, and other Oriental peoples for any western foreigner.
• noun The signature or indorsement of a person holding the privilege of franking mail-matter, written or impressed on the wrapper in token of the right of the inclosure to pass free.
• noun A letter thus indorsed, sent by mail free of postage.
• To send or cause to be sent by public conveyance free of expense: as, to frank a letter.
• Hence To facilitate the passage or movements of; give the right of way to, as a traveler.
• In carpentry, to form the joint of, as that of a window-sash where the crosspieces of the frame intersect each other, by cutting away no more wood than is sufficient to show a miter.
• noun A former spelling of franc.
• Free; open; unrestrained; unconditioned.
• Liberal; generous; not niggardly.
• Free from disguise or concealment; candid in utterance; sincere and unreserved in manner: as, a frank disposition; a frank avowal.
• Freely disclosed; clearly manifest; undisguised; indubitable: as, frank ignorance or poverty.
• Unrestrained; using free license.
• Synonyms Open, Ingenuous, etc. (see candid); plain, unreserved, undisguised.
• noun A pigsty; a pen for fattening boars.
• Sty-fed. See I.
• To shut up in a frank or sty: usually with up.
• To feed; cram; fatten.
• noun A name of the heron, Ardea cinerea.

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

• noun obsolete A pigsty.
• adjective rare Unbounded by restrictions, limitations, etc.; free.
• adjective Free in uttering one's real sentiments; not reserved; using no disguise; candid; ingenuous
• adjective obsolete Liberal; generous; profuse.
• adjective Unrestrained; loose; licentious; -- used in a bad sense.
• noun (Ethnol.) A member of one of the German tribes that in the fifth century overran and conquered Gaul, and established the kingdom of France.
• noun A native or inhabitant of Western Europe; a European; -- a term used in the Levant.
• noun A French coin. See Franc.
• transitive verb obsolete To shut up in a frank or sty; to pen up; hence, to cram; to fatten.
• noun (Zoöl.), Prov. Eng. The common heron; -- so called from its note.
• transitive verb To send by public conveyance free of expense.
• transitive verb To extempt from charge for postage, as a letter, package, or packet, etc.
• noun The privilege of sending letters or other mail matter, free of postage, or without charge; also, the sign, mark, or signature denoting that a letter or other mail matter is to go free of postage. Called also the franking privilege.

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

• noun UK the grey heron.
• noun A hot dog or sausage.
• adjective honest, especially in an manner that seems slightly blunt.
• noun uncountable Free postage, a right exercised by governments (usually with definite article).
• noun countable The notice on an envelope where a stamp would normally be found.
• verb To place a frank on an envelope.