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:
“Sekkha Sutta (SN 45.13)” and “Sekkha Sutta (AN 3.85).”
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.”