TDs

TDs is an acronym used in several fields. The two most common meanings are touchdowns in gridiron football and total dissolved solids in water quality analysis. In other contexts, it can denote term deposits or tactical data systems, but these are less central to common references.

In sports, a touchdown, or TD, is a scoring play in American and Canadian football. It is worth six points. A team scores a TD by advancing the football into the opponent's end zone by carrying, catching a pass in the end zone, or recovering a loose ball in the end zone during play. After scoring a touchdown, the team has an opportunity to attempt an extra point (a kick worth one point) or a two-point conversion (from the two-yard line) to add additional points. TDs are a major statistical category for players who score, including running backs, receivers, quarterbacks (on passes that result in a TD), and return specialists. The distribution of TDs across players and teams is often cited in season summaries, awards, and records. TDs can also be credited to defensive or special teams units when they recover a fumble, intercept a pass, or return a kickoff or punt for a touchdown.

In water quality, total dissolved solids is a parameter that represents the combined content of inorganic salts and some organic matter dissolved in water. It is typically measured in milligrams per liter (mg/L) or parts per million (ppm). Higher TDS levels can influence taste, hardness, and conductivity, though TDS itself does not indicate specific contaminants. In drinking-water guidelines, a low to moderate TDS is usually preferred for taste and aesthetic reasons, with recommended levels often below 500 mg/L in many jurisdictions. Removal methods include reverse osmosis, distillation, and ion exchange.