What that means is that the teachers' break is shorter because they are working on those conference days.

Our Thanksgiving week is somewhat like that. The first two days are designated as teacher inservice days. We have to earn two trade days of workshops in the previous summer or sometime during the school year (after school or on weekends) to count for those trade days or we are docked for those two days (at full pay -- not at the pro-rated full-year rate). That's A LOT of money if we don't take care of those trade day hours.

Our Christmas breaks are always at least two weeks -- preferably 2 1/2. One year they only gave us a week and a half. That completely sucked (and they heard about it - never to be repeated again).