| ASTACOLOGY | From Greek for "lobster", a term for the science or study of crayfish (10) |
| NIPPER | A carter, a costermonger or a navvy's boy assistant; a chela of a crab or a lobster; a child; a cutpurse or a pickpocket; a creature that bites or pinches; or, one of a pair of cuffs (6) |
| PHARMACOLOGY | The science or study of drugs |
| SEMIOLOGY | The science or study of signs |
| OOLOGY | The science or study of birds' eggs (6) |
| CALTECH | Byname for the science and engineering institute in the U.S. city of Pasadena established in 1891 (7) |
| ANATOMY | From "dissection, cut", word for the science of bodily structure (7) |
| ASTRO | Prefix for the science of 4-Across |
| HARMONY | A combination of simultaneously sounded musical notes producing an aesthetically agreeable sound; the art, science or study of chords; or, a collation of parallel narratives (7) |
| CRUSTACEAN | Surface on a sea yielding zero for lobster or similar |
| DACTYLIOLOGY | From Greek for "finger", a term for the study or lore of finger-rings or of engraved antique gems (12) |
| ORCHIDISTS | Botanists who cultivate or study the flowers used as floral emblems of countries including Belize, Colombia, Singapore and Venezuela (10) |
| OROGRAPHY | Science or study of mountains (9) |
| OROLOGY | Science or study of mountains (7) |
| ETAGE | French word for a floor or storey; or, a term for the grouping of cloud height in meteorology (5) |
| SALOPIANS | A term for the natives or inhabitants of the county of Shropshire (9) |
| SUMPSIMUS | Taken from a Latin prayer, a term for the correct equivalent of an incorrect but popular expression |
| MOUNTS | In the hobby or study of philately, another name for stamp hinges (6) |
| PLAINS | A term for the many Native American tribes once occupying an area from the Mississippi river to the Rocky mountains (6,7) |
| INDIANS | A term for the many Native American tribes once occupying an area from the Mississippi river to the Rocky mountains (6,7) |
