The Collaborative International Dictionary of English v.0.48:

Pennant \Pen"nant\ (p[e^]n"nant), n. [OE. penon, penoun, pynoun,
   OF. penon, F. pennon, fr. L. penna feather. See Pen a
   feather, and cf. Pennon, Pinion.] (Naut.)
   (a) A small flag; a pennon. The narrow pennant, or long
       pennant (called also whip or coach whip) is a long,
       narrow piece of bunting, carried at the masthead of a
       government vessel in commission. The board pennant is
       an oblong, nearly square flag, carried at the masthead of
       a commodore's vessel. "With flags and pennants trimmed."
       --Drayton.
   (b) A rope or strap to which a purchase is hooked.
       [1913 Webster] Pennate

WordNet (r) 3.0 (2006):

pennant
    n 1: the award given to the champion [syn: pennant, crown]
    2: a flag longer than it is wide (and often tapering)
    3: a long flag; often tapering [syn: pennant, pennon,
       streamer, waft]

Moby Thesaurus II by Grady Ward, 1.0:

42 Moby Thesaurus words for "pennant":
   Dannebrog, Jolly Roger, Old Glory, Star-Spangled Banner,
   Stars and Stripes, Union Flag, Union Jack, and blue, banderole,
   banner, banneret, black flag, blue ensign, bunting, burgee,
   coachwhip, color, colors, ensign, flag, gonfalon, gonfanon, guidon,
   house flag, jack, long pennant, merchant flag, national flag,
   oriflamme, pendant, pennon, pennoncel, red, red ensign,
   royal standard, signal flag, standard, streamer, swallowtail,
   tricolor, vexillum, white