The Collaborative International Dictionary of English v.0.48:

Salvo \Sal"vo\, n.; pl. Salvos. [L. salvo jure, literally, the
   right being reserved. See Safe.]
   An exception; a reservation; an excuse.
   [1913 Webster]

         They admit many salvos, cautions, and reservations.
                                                  --Eikon
                                                  Basilike.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Salvo \Sal"vo\, n. [F. salve a discharge of heavy cannon, a
   volley, L. salve hail, imperat. of salvere to be well, akin
   to salvus well. See Safe.]
   1. (Mil.) A concentrated fire from pieces of artillery, as in
      endeavoring to make a break in a fortification; a volley.
      [1913 Webster]

   2. A salute paid by a simultaneous, or nearly simultaneous,
      firing of a number of cannon.
      [1913 Webster]

WordNet (r) 3.0 (2006):

salvo
    n 1: an outburst resembling the discharge of firearms or the
         release of bombs
    2: rapid simultaneous discharge of firearms; "our fusillade from
       the left flank caught them by surprise" [syn: fusillade,
       salvo, volley, burst]
    3: a sudden outburst of cheers; "there was a salvo of approval"