In a handicap race like The California Dreamin‘ for 3-year-olds on the turf at Del Mar this Sunday, a penalty or disadvantage is given to horses who are judged to be more likely to win the race. In an attempt to make the competition more equal the horses are assigned additional weight (their handicap) based upon their past performance.

Eldaafer Winning the 2009 Brooklyn Handicap (AP Photo provided by NYRA)
In common speech, handicap refers to a wide range of disabilities. The interesting part is the change in usage. Originally the handicap weight was added to the faster contestant but it’s meaning has evolved over the past couple of centuries. Over time, the meaning of handicap has changed from the weight that slows a superior horse down to the common understanding that simply connotes some sort of disadvantage.
In golf a handicap is a numerical measure of an amateur’s playing ability based on the tees played for a given course. I’m not an experienced golfer and I don’t understand this formula but it is explained here.
By the way, the high weight (and probable post time favorite) in the California Dreamin’ Handicap is the #9 horse Bold Chieftain carrying 123lbs. Bold Chieftain has won this race the past two years and he is going for his personal California Dreamin’ trifecta. The horses with the low weight assignments are getting 10 lbs off the favorite: the #3 Suit Yourself and the #6 Bert’s Law, each at 113lbs. I give Bert’s Law a chance of rounding out an exacta with the high weight favorite.