APLs

APLs is an acronym that may refer to several distinct concepts across different fields. In computing, medicine, physics, and mathematics, the exact meaning depends on context. The most widely encountered senses are A Programming Language (APL), acute promyelocytic leukemia (APL), Johns Hopkins Applied Physics Laboratory (APL), and average path length (APL).

In computing, APL refers to a family of array programming languages originated by Kenneth E. Iverson in the 1960s. Noted for concise notation and powerful operators that manipulate whole arrays, APL supports dyadic and monadic functions and uses a rich set of non‑ASCII symbols in many implementations. Modern versions often provide ASCII keyboards.

Acute promyelocytic leukemia, a form of acute myeloid leukemia, is a hematologic malignancy characterized by accumulation of abnormal promyelocytes. It can cause bleeding abnormalities due to coagulopathy. Treatment has improved markedly with all-trans retinoic acid (ATRA) and arsenic trioxide, yielding high cure rates when initiated promptly.

Applied Physics Laboratory, the Johns Hopkins University’s Applied Physics Laboratory (APL), is a not-for-profit research center that conducts defense, space, and national security-related projects. Since its founding, APL has developed technologies ranging from guidance systems to autonomous systems, and it operates under collaborations with government agencies and industry.

In graph theory and network science, average path length (APL) denotes the average of the shortest path lengths between all pairs of nodes in a graph. It serves as a global measure of network efficiency and is sensitive to network topology and size.