Notes on Spacecraft in the Star Wars Universe
Warship Classification--similar to Earth warship classification
I.  Capital Ships--in real life terms, Webster defines capital ship:
           "an armored surface vessel of war, other than an aircraft carrier, carrying guns exceeding 8-inch caliber"
       thus, in Star Wars, the following are NOT capital ships:  Carriers, Liners, Yachts, Transports, etc.
       The following are the basic classifications of Capital Ship from largest to smallest: 
All quotes from Webster's Second College Edition; examples and notes from Star Wars Universe
             Dreadnaught (>Dreadnought, 1st such ship, British)--"any large, heavily armored battleship with many                                                                                             powerful guns"
                                                                                               Example:  Invincible-class Dreadnaught                      Battleship (an Americanism)--"any of a class of large warships with the biggest guns and very heavy                                                              weapons"
                 Synonym:  Battlewagon (an Americanism, slang)         Example:  Trade Federation Battleship
             Battle Cruiser--"a large warship with longer range and greater speed and maneuverability than a                                                 battleship, but less heavily armored"
                                                                                               Example: Hapes Nova-class Battle Cruiser                Cruiser--"any of several types of fast and maneuverable warship somewhat smaller than a battleship                                 and having less armor and firepower"               
                                                                                               Example:  MC80 Star Cruiser    
                           note:  "Cruiser" can be used to refer in a non-military sense to refers to various ships such as                             luxury liners, yachts, or virtualy any sizable starship (i.e, the Corellian Space Cruiser, which                              is certainly not a cruiser in the military sense:  it has no weapons, and is smaller than                                         gunships built by the same manufacturer; the same is true for CR90 Corvettes, Nebulon-B                                 Frigates, Imperator-class Star Destroyers, and Jabba's Star Jewel being referred to as                                       "cruisers" by various sources); also, many writers mistakenly believe cruisers to be smaller                                than destroyers, i.e., the erroneously named Namana-class Light Cruisers are 100 metres
                           shorter than the Bakura-class Destroyers from the same manufacturer.
             Battle Destroyer--this term is only found in the book Hard Merchandise, and the context suggests it is                                         larger and more heavuly armored than an ordinary destroyer         
             Destroyer--"a small, fast, highly maneuverable warship armed with 3-inch or 5-inch guns, depth                                         charges, torpedoes, etc."   
                                                                                               Example: Imperator-class Star Destroyer     
                           note:  a destroyer is technically a ship smaller than a cruiser.  The term "Star Destroyer" is                                 non-technically often given as a nickname to any Imperial warship similar in design to the                                  Imperator-class and Victory-class destroyers.  For example, large Imperial warships                                         nicknamed "Super Star Destroyers" are not really destroyers at all:  the Allegiance is a                                       cruiser-scale vessel, and the Executor-class Command Ships are Battle Cruisers.                  
             Frigate--"a...warship between a corvette and a destroyer"
                 Synonym:  Manowar (short for Man-of-war)              Example:  Galleon-class Star Frigate                           Corvette--"1.  a...warship...smaller than a frigate....  2.  a small, fast...warship of about 1,000 tons,                                         used for anti-submarine and convoy duty"
                                                                                               Example:  Lianna-class Corvette          
             Monitor (>Monitor, first such ship, American)--"an armored warship...with a low freeboard, low flat                                                                                       deck, and heavy guns fitted in one or more revolving                                                                                      turrets"
                Synonym:  Gunship                                                   Example:  DP20 Gunship               
II.  Small Comatants
           these include various Patrol Boats (synonymouswith Gunboats), Missile Boats, and various Patrol Craft
          Examples:  PB-950 Patrol Boat, Xg-1 Gunboat, Xm-1 Missile Boat, IPV-1 System Patrol Craft
III.  Other Warships
           Carriers and Landing Ships are warships of various sizes whose assault importance is not heavy                         weaponry, but in carrying and deploying fighters (in the former case) or troops (in the latter case)
           Examples:  Endurance-class Fleet Carrier, Escort Carrier, C-9979 Landing Ship 
IV.  Support Craft
           Usually ships not built for that support a Fleet:  i.e., fuelers, repair ships, couriers, shuttles
           A few of these craft do have significant weaponry, and are made to defend themselves in military fields              of operations; ragtag fleets sometimes rely on them as primary warships   
           Examoles:  Calamarian Tanker, Medium Transport, Class-7 Repair Vessel, Delaya-class Courier,                                        Lambda-class Shuttle, Neimoidian Shuttle, Fleet Hauler, Galleon, etc.
V.  Fighters and Bombers
           These are the equivalents in Starfleets to the planes of Earth airforces.

NOTES:
"Pocket" used as an adjective refers to something that is a smaller variety than the norm.  For example, the Marauder-class Corvette is sometimes classified as a "Pocket Cruiser" because is is smaller than a ship usually classified as a Cruiser

"Customs," "Picket," and "Patrol" craft are often given designations of captal ship-type names, although way to small to classify as such in military terms.  I.e., the Customs Guardian-class Light Cruiser, 42 metres long, is way too small and lightly aremd to be a true military cruiser.  Likewise, the so-called Imperial Customs "Frigate" is smaller than the smae manufacturer's Imperial Custroms Vessel, which is classified as a LIGHT Corvette in military terms!