A gyre is another name for a swirling vortex. Ocean gyres are large swirling bodies of water that are often on the scale of a whole ocean basin or 1000 s of kilometers across (hundreds to thousands of miles across).
Lean meats are meats with a relatively low fat content. Skinless chicken and turkey and red meat, such as pork chops, with the fat trimmed off are examples of lean meat.
Different animals have different body compositions, and therefore their meat varies in nutrient profile. For example, turkey is considerably leaner than beef, meaning it has much less fat, but it has about the same amount of protein per ounce.