The Collaborative International Dictionary of English v.0.48:

Overload \O`ver*load"\, v. t. [imp. & p. p. Overloaded; p. pr.
   & vb. n. Overloading.] [Cf. Overlade.]
   To load or fill to excess; to load too heavily.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Overload \O"ver*load`\, n.
   An excessive load; the excess beyond a proper load.
   [1913 Webster]

WordNet (r) 3.0 (2006):

overload
    n 1: an electrical load that exceeds the available electrical
         power
    2: an excessive burden [syn: overload, overburden]
    v 1: become overloaded; "The aerator overloaded"
    2: fill to excess so that function is impaired; "Fear clogged
       her mind"; "The story was clogged with too many details"
       [syn: clog, overload]
    3: place too much a load on; "don't overload the car" [syn:
       overload, surcharge, overcharge]

Moby Thesaurus II by Grady Ward, 1.0:

106 Moby Thesaurus words for "overload":
   adorn, bale, bear hard upon, burden, burdening, burthen, cargo,
   charge, charging, choke, congest, congestion, convolute, cram,
   crowd, cumber, cumbrance, deadweight, decorate, drag, drench,
   elaborate, embellish, embroider, encumber, encumbrance,
   engorgement, enrich, festoon, flourish, freight, gild, glut,
   gluttonize, go hard with, go ill with, gorge, hamper, handicap,
   hindrance, hyperemia, impede, impediment, incubus, incumbency,
   involve, jam, jam-pack, lade, lading, lie on, load,
   load with ornament, loading, millstone, oppress, oppression,
   ornament, overbrimming, overburden, overcharge, overfeed, overfill,
   overflow, overfreight, overfullness, overlade, overlay, overspill,
   overstuff, overtax, overtaxing, overweigh, overweight,
   overweighting, pack, plethora, press hard upon, pressure,
   repletion, rest hard upon, saddle, saddle with, saddling, satiate,
   satiety, saturate, saturation, soak, strain, stuff, supercharge,
   superincumbency, supersaturate, supersaturation, surcharge,
   surfeit, tax, taxing, trick out, try one, varnish, weigh down,
   weigh heavy on, weigh on, weigh upon