Yes. A sekkha is a Noble Person at or above the Sotapanna Anugami stage, training to be an Arahant (Asekha).
Two suttas explain a sekha:
The English translations can be improved. For example, the following verse in the second sutta “Adhisīlampi sikkhati, adhicittampi sikkhati, adhipaññampi sikkhati. Sikkhatīti kho, bhikkhu, tasmā sekhoti vuccatīti” can be a bit better translated as:
“They train with Ariyakanta sila (Adhisīla,) they cultivate defilement-free thoughts (dhicitta) with the comprehension of Tilakkhana (adhipañña.) That’s why they are called a ‘trainee’.”
See #4 of “Sotapatti Aṅga – The Four Qualities of a Sotāpanna” for a description of “ariyakanta sila.”