1R

1r is a string that can refer to different concepts depending on the context, and there is no single universal meaning associated with it. In electronics and electrical engineering, 1R appears in resistor value markings where the letter R stands in for a decimal point. This notation avoids the use of a dot on some parts labeling. For example, a resistor marked 1R0 equals 1.0 ohm, and 4R7 equals 4.7 ohms. Since 1R by itself is not a standardized code, many suppliers use 1R0 or 1R00 to indicate 1 ohm; always verify with the component’s datasheet or bill of materials.

In historical currency notation, the letter r has sometimes been used as an abbreviation for ruble in Russian-language documents. In that usage, 1r would denote one ruble, appearing in archival price lists and accounting records from periods before modern decimalization or currency reforms. In modern contexts the ruble is usually denoted by the symbol ₽ or by “R” in some English-language texts, but the exact form 1r is uncommon today.

In chemistry and pharmacology, the uppercase R and S designations denote absolute configuration at chiral centers; 1R is used in systematic names to indicate the R configuration at carbon 1. The lowercase 1r is not the standard symbol for this usage, and case matters in these conventions. Beyond these fields, 1r can also appear as a model number, revision code, or catalog identifier assigned by a company or project, where its meaning is defined by the issuer.

Because 1r has multiple distinct meanings, the intended interpretation is determined by the surrounding context.

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