Why does the Eastern Orthodox Church call the 49 days following Easter, Pentecost, and the Western Church does not?

Just from Wikipedia I have found that the 49 days before Pentecost are called "Pentecost" (there's even "Mid-Pentecost" which is the midpoint from Easter to Pentecost) but in the Western Church I can't seem to find if there is even a name for this time frame. I have found some looser comments that "the 49 days before Pentecost can also be called Pentecost" but I don't know if it's just so loose that they're mixing Western and Eastern. Is there a name for this time frame in the Western Church? And is there a circumstance where the Western Church refers to this time as Pentecost?