Rumex sanguineus, Redvein or Bloody Dock.

Here is a link that might be useful: Google image results

I don't think the veining is red enough or pronounced enough for R sanguineus. Could be broad leaved dock, R obtusifolius. Plants are variable and also hybridise in nature.

Here is a link that might be useful: Rumex obtusifolius

Rumex sanguineus shows its beautiful red veining even when young leaves are sprouting in the spring - much more red veining than just the central midrib. Both the R. obtusifolius and R. crispus that grow around my place show red color when first coming up in the spring even though the R. crispus doesn't have much or any color later on in the growing season.

Given the leaf shape, I would say R. obtusifolius but early season leaves can be a bit atypical compared to the plant later on in the season.

FataMorgana