Reference
Thermometer puzzle glossary
The vocabulary used in thermometer puzzles, in our rules and in the strategy guide.
- Thermometer
- A chain of orthogonally connected cells with a bulb at one end and a tip at the other. Every cell of the grid belongs to exactly one thermometer.
- Bulb
- The rounded end of a thermometer. Mercury always starts here, so a thermometer with any mercury has a filled bulb.
- Tip
- The flat, closed end of a thermometer, farthest from the bulb. It can only be filled if the whole thermometer is full.
- Mercury
- The liquid that fills thermometers. A mercury cell is a filled (shaded) cell that counts toward its row and column clues.
- Air
- A cell known to be empty. Marking air (shown as ×) is optional, but it helps you keep track of deductions.
- Clue
- A number outside the grid giving the exact count of mercury cells in that row or column.
- Fill level
- How many cells of a thermometer contain mercury, counted from the bulb. It ranges from 0 (empty) to the thermometer's length (full).
- Straight thermometer
- A thermometer lying entirely in one row or one column.
- Curved thermometer
- A thermometer that bends around one or more corners, so it can pass through several rows and columns.
- Given cell
- A cell revealed at the start of the puzzle (shown on a tinted background) to guarantee a single solution.
- Flow
- The rule that mercury propagates back to the bulb and air propagates forward to the tip. It is the most-used deduction in the genre.
- Squeeze
- A deduction where a line needs more mercury than the other thermometers can supply, which forces a minimum fill level on one thermometer.
- Ceiling
- A deduction where a small clue caps how much mercury a thermometer can add to a line, forcing cells beyond that point to be air.
- Capacity
- The most mercury a line could still hold given the current state of every thermometer touching it.
- Unique solution
- A puzzle with exactly one valid answer. Every puzzle on this site is checked by a solver to make sure it has one.