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.
Chicken is a lean meat. Lean meat is a good source of protein with a lower fat content and therefore a lower calorie content. Lean meat is generally regarded as a safe source of protein there have been some concerns about antibiotic use in poultry farms.