Granted this is a semantics thing.
But there is a bit of history involved which might end the confusion.
Mrs.Takata called what she did initiations.
standard reference
1 a : the act or an instance of initiating b : the process of being initiated by the rites, ceremonies, ordeals, or instructions with which one is made a member of a sect or society or is invested with a particular function or status
2 : the condition of being initiated into some experience or sphere of activity KNOWLEDGEABLENESS.
this fits with a model of a ceremony or rite.
Apparently it was Barbara Ray who called what she did Attunements
at.tune
1 : to bring into harmony : TUNE
2 : to make aware or responsive
- at.tune.ment /-m&nt/ noun
which fits with her idea of Reiki as a "ray"
both do fit the process-we are initiated into this energy work called Reiki, and we are more attuned (in tune , harmonious) with the radiance, the light.
Faith