round-trip light time round-topped • round-trip ticket · · · Info · Definitions · Synonyms · Characters · · round-trip light time · · Text Common · · Latin · · Scripts 21 · · Length 4 · · Syllables Definitions · · · (noun) the elapsed time it takes for a signal to travel from Earth to a spacecraft (or other body) and back to the starting point. Synonyms: round-trip light time, RTLT. · · Noun Definition 1 Synonyms · · · rtlt · · Synonym 1 Characters · · space U+0020 - hyphen-minus U+002D d latin small letter d U+0064 e latin small letter e U+0065 g latin small letter g U+0067 h latin small letter h U+0068 i latin small letter i U+0069 l latin small letter l U+006C m latin small letter m U+006D n latin small letter n U+006E o latin small letter o U+006F p latin small letter p U+0070 r latin small letter r U+0072 t latin small letter t U+0074 u latin small letter u U+0075