Word formation – Using all the letters E, S, T, R exactly once, how many meaningful English words can be formed?

Introduction / Context:
Anagram items often involve common letter clusters. With E, S, T, R, there are several permutations, but only a subset will be accepted dictionary words. The task is to count how many 4-letter meaningful English words use all letters exactly once.

Given Data / Assumptions:

• Letters: {E, S, T, R}.
• All letters must be used once in each word.
• Meanings must be recognized in standard English dictionaries.

Concept / Approach:
Two well-known words appear from this set: “REST” and “ERST.” “REST” is extremely common (to relax; remainder). “ERST” is older/poetic (meaning “formerly”), but it is a recognized English word frequently accepted in reasoning and vocabulary tests. Other permutations such as “RETS,” “TRES,” or “SERT” are not accepted as standalone words in general usage.

Step-by-Step Solution:
Check main candidates: REST (valid), ERST (valid), plus test others for dictionary acceptance.Confirm there are exactly two standard words.

Verification / Alternative check:
Consult reputable dictionaries; “ERST” appears in archaic/poetic label but is legitimate and commonly treated as valid in competitive exam word-formation questions.

Why Other Options Are Wrong:

• None/One: Under-count the legitimate pair.
• Three/Four: Over-count by including nonwords or abbreviations.

Common Pitfalls:
Discarding archaic but valid words (like ERST) or, conversely, accepting abbreviations. Competitive exam convention typically counts “ERST.”

Final Answer:
Two