CNSL is an acronym that can refer to several terms in different fields. In medicine, central nervous system lymphoma (CNSL) is a form of non-Hodgkin lymphoma that affects the brain, spinal cord, meninges, or eyes. It may be primary CNS lymphoma (PCNSL) when confined to the central nervous system or secondary involvement from systemic disease. Presentation varies but can include headaches, cognitive or personality changes, focal neurological deficits, seizures, or visual symptoms. Diagnosis involves neuroimaging (MRI or CT), lumbar puncture with CSF analysis, and sometimes brain biopsy. Treatment commonly relies on high-dose methotrexate–based chemotherapy and may be followed by radiotherapy, depending on patient factors. Prognosis is influenced by age, performance status, and extent of disease. Cashew nut shell liquid (CNSL) is a natural resin obtained from the shells of cashews. It contains phenolic compounds such as anacardic acids, cardanol, and cardols. CNSL is used as a renewable raw material in coatings, varnishes, and specialty resins, and as a modifier in polymer formulations. It can be processed into natural CNSL products or polymerizable derivatives that cure to form thermosetting resins. Because some components can be skin irritants or sensitizers, handling CNSL requires appropriate safety measures.