Octa can refer to different things depending on the context. Here are some possible meanings:

1. Okta: It is an American identity and access management company that provides cloud software to help companies manage and secure user authentication into applications.

2. Optical Coherence Tomography Angiography (OCTA): It is a non-invasive imaging technique that generates angiographic images in a matter of seconds by comparing the decorrelation signal between sequential OCT b-scans taken at precisely the same cross-section to construct a map of blood flow. OCTA allows volumetric angiography images to be captured in a matter of seconds, providing concurrent information about tissue structure and blood flow for research and diagnostic purposes. OCTA has been shown to be a useful imaging modality for the evaluation of common ophthalmologic diseases such as AMD, diabetic retinopathy, artery and vein occlusions, and glaucoma.

3. Orange County Transportation Authority (OCTA): It is a transportation agency that provides bus, freeway, rail, bike, walking, and rideshare programs to keep residents and commuters moving throughout Orange County.

Without more context, it is difficult to determine which Octa is being referred to.