a distinct layer or level within a system, often conceived as having depth or hierarchy
a problem or question that is confusing and needs a lot of skill or effort to solve or answer
a section of additional material that is usually added at the end of a book
a single-celled microorganism that typically reproduces by cell division and can be found in various environments, including soil, water, and living organisms
a shell beads used by some Native American tribes as currency or ceremonial items
a device with a long thin bar and a weight at the end that swings side to side to keep a clock working
the wall separating the audience and the stage in a theater hall, including the arch on its top
a tarred fiber used for caulking seams in wooden ships and as insulation in plumbing
a single piece of information or a reference point used in analysis or measurement
a concise collection or summary of information, typically presented in a single volume or document
severe criticism or public condemnation, often directed at someone's actions or behavior that is considered shameful or disgraceful
a point or support on which a lever pivots or rotates in order to lift or move objects
an unpleasant or noxious odor, typically emanating from decaying matter or industrial processes
a period of one thousand years, usually calculated from the year of the birth of Jesus Christ
a temporary suspension or halt of an ongoing activity, often imposed by an authority
a formal expression of praise or tribute, typically delivered in speech or writing
a facility offering care for patients with mental or medical conditions needing extended treatment
a questionable or unproven remedy or treatment, often sold with exaggerated claims of effectiveness