Beta is the second letter is the Greek alphabet, and, naturally, the source of the final syllable in the word alphabet. "Like the names of most other Greek letters, the name of beta was adopted from the acrophonic name of the corresponding letter in Phoenician, which was the common Semitic word *bayt ('house')."
A beta male is considered to be sensitive, nurturing, conflict-averse communicator. OR have characteristics to be avoided. It depends on who you ask.
Beta testing is the software development phase which "generally begins when the software is feature complete but likely to contain a number of known or unknown bugs... The focus of beta testing is reducing impacts to users, often incorporating usability testing... This is typically the first time that the software is available outside of the organization that developed it.
Beta-Carotene is a strongly colored red-orange pigment abundant in plants and fruits such as carrots, pumpkins and sweet potatoes.
Beta blockers "treat a variety of conditions, such as high blood pressure, glaucoma and migraines."
Founded in 1922, Beta Beta Beta (TriBeta) is "a society for students, particularly undergraduates, dedicated to improving the understanding and appreciation of biological study and extending boundaries of human knowledge through scientific research."
In nuclear physics, beta decay (β-decay) "is a type of radioactive decay in which a proton is transformed into a neutron, or vice versa, inside an atomic nucleus. This process allows the atom to move closer to the optimal ratio of protons and neutrons."
Like alpha, beta is also a financial term though I would be hard pressed to explain it.
There are a lot more Beta terms. If you are of a certain age, you may remember Betamax, a video recording tape that was technologically superior to VHS, but lost out in the marketplace.