MTRA's Guide to Race Types & Restrictions/Conditions

Mdn Maiden Only horses who have never won a race can enter a Maiden.  Maiden races typically have smaller purses and are filled with "unknowns."  Maidens are usually offered by age and distance, and sometimes only to specific genders (i.e. fillies/mares).  This is usually where most horses begin their racing careers.
Alw Allowance An allowance is for horses who have won a maiden, but who are not necessarily for sale. Published and consistent conditions determine weight allowance according to previous number of victories, gender, etc.  This is usually where Maiden winners go if they're not quite yet seasoned enough or ready for stakes company.  Though any horse may enter an allowance regardless of whether or not it's won, it's usually not recommended that you send non-winners to these races.  Allowances are considered undercard races (i.e. run on the card "beneath" the stakes, usually touting smaller purses than stakes races), and are often the next step up in the ladder towards Stakes racing.
rAlw Restricted Allowance A restricted allowance is just an allowance with restrictions to help "level" the playing field and give everyone a more even chance to win.
S Stakes Race These are sometimes called "Money" or "Black-Type" races, since it is more prestigious and lucrative to win or place well in a stakes race.  Generally, horses who enter a stakes race have won a few races (including their maiden), and have probably proven themselves at the Allowance ranks.  They may not be ready for graded stakes company, or they may have been struggling at the graded stakes levels.  Weights are indicated by published condition such as age, gender, victories, etc.
rS Restricted Stakes A stakes race with restrictions to keep the field competitive and fairly evenly matched in experience and/or form.
G3 Grade/Group 3 Stakes A stakes race for horses of some proven significance
G2 Grade/Group 2 Stakes A stakes race for horses of proven national significance
G1 Grade/Group 1 stakes A stakes race for horses of proven international significance
H Handicap Race Handicap races are stakes races (when in the U.S.) in which the entrants are assigned weight based on past performance, wins, and a variety of other factors to attempt to run all horses with the same advantage.  Ideally, an Allowance Winner would have the same chance to win as the G1 stakes horse, since the stakes horse would be weighted substantially whereas the inexperienced or younger winner wouldn't be carrying nearly so much.  In Europe, Handicap races are another name for what our Allowance races are, and should not be confused as being stakes!
T Turf Races run on the grass track instead of the main dirt track.


Progression of Race Types (lowest to highest): Mdn--rAlw--Alw--rS--S--G3--G2--G1
Some horses can skip some levels, but the levels you rarely see skipped in the MTRA are Mdn and the Alw levels


Race Types with Abbreviations & Definitions

NSW Non-Stakes Winners Restricted to horses who have not won a stakes race.
NW2 Non-Winner of 2 races Restricted to horses who have not won 2 or more races, regardless of type.
NW$k Non-Winner of X amount of earnings Restricted to horses who have not earned a designated amount of lifetime earnings.
NW o/t M/C Non-Winner other than Maiden/Claiming Restricted to horses who have not won a race other than a maiden race - they are eligible to run in this type of race regardless of wins so long as none of them are allowance or stakes wins.
N1x Non-Winners of 1 race Non-winners of a race other than Maiden or Starter races.  Used for Non-Winners of up to 5 races "other than."
N1Y Non-Winners of 1 race in a given year Non-Winners of 1 race in or since a given time period (by year).
N2L Non-Winners of 2 races (or more) lifetime Cannot have won more than 2 races in the entrants lifetime.
N$Y Non-Winners of $ in a given year Cannot have won more than a given amount of money in a specific time period
N1m Non-Winners of 1 at a mile or over Non-winners of 1 race (or more) at a mile or more in a given period of time
N$mY Non-Winner of $ OR 1m in given period Non-winners of a given amount of money -or- over 1m in a specific period of time
N1S Non-Winners of 1 stakes race Non-winners of a stakes (or more if the number is different) in a horse's lifetime
N1T Non-Winners of 1 turf race Non-winners of a turf race in a horse's lifetime
NmT Non-Winners of 1 turf race at a mile or more Non-winners of a turf race at 1m or more in a horse's lifetime
NC Race with no conditions/restrictions Race has no conditions or restrictions for entering
C Race with multiple conditions Race with multiple conditions or restrictions for entering
Sp Wt Special Weight Maiden Special Weight (for horses who have never won) - weights by gender/age