ACO, AcO, or Aco may refer to:
Acorus calamus (also called sweet flag or calamus, among many common names) is a tall perennial wetland monocot of the Acoraceae family, in the genus Acorus.
Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound.
Aconitum (/ˌækəˈnaɪtəm/), commonly known as aconite, monkshood, wolf's bane, leopard's bane, mousebane, women's bane, devil's helmet, queen of all poisons, or blue rocket, is a genus of over 250 species of flowering plants belonging to the family Ranunculaceae.
Acorn Computers Ltd. was a British computer company established in Cambridge, England, in 1978. The company produced a number of computers which were especially popular in the UK, including the Acorn Electron and the Acorn Archimedes.
Acoma Pueblo (/ˈækəmə/; Western Keresan: Haak'u; Zuni: Hakukya; Navajo: Haakʼoh) is a Native American pueblo approximately 60 miles (97 km) west of Albuquerque, New Mexico in the United States.
An acoustic metamaterial is a material designed to control, direct, and manipulate sound waves as these might occur in gases, liquids, and solids.
In 2009, workers at offices of the Association of Community Organizations for Reform Now (ACORN), a non-profit organization that had been involved for nearly 40 years in voter registration, community organizing and advocacy for low- and moderate-income people, were secretly recorded by conservative activists Hannah Giles and James O'Keefe – and the videos "heavily edited" to create a misleading impression of their activities.
The Acorn Electron is a budget version of the BBC Micro educational/home computer made by Acorn Computers Ltd.
The acorn, or oak nut, is the nut of the oaks and their close relatives (genera Quercus and Lithocarpus, in the family Fagaceae).