What is considered to be meat for the Lenten Season? Beef only? How about chicken, pork, or lamb?

Beef, chicken, pork and lamb are all meats. Fish and other seafoods are not. I take it you're trying to abstain from meat for Lent? In my belief system observing Lent is unnecessary but good luck.

In the Latin Church, abstinence means refraining from eating the meat from mammals or fowl, and soup or gravy made from them. Fish is allowed. Traditionally, the laws of abstinence apply to all aged 7 and over, but the new Code of Canon Law applies it to all who have completed their 14th year.