veECRV stands for voting escrow ECRV. They are your ECRV locked for voting. The longer you lock your ECRV for, the more voting power you have (and the bigger boost you can reach). E.g. You can vote lock 1,000 ECRV for a year to have a 250 veECRV weight. Each ECRV locked for four years is equal to 1 veECRV.