This article is about a Sanskrit word. You may be looking for the acronym RTU

RTU

A remote terminal unit is a microprocessor-controlled electronic device that interfaces objects in the physical world to a distributed control system or SCADA by transmitting telemetry data to the system and/or altering the state of connected objects based on control messages received from the...

(note that Wikipedia can be case-sensitive).

Ritu () in Vedic Sanskrit

Vedic Sanskrit

Vedic Sanskrit is an old Indo-Aryan language. It is an archaic form of Sanskrit, an early descendant of Proto-Indo-Iranian. It is closely related to Avestan, the oldest preserved Iranian language...

 refers to a fixed or appointed time, especially the proper time for sacrifice

Sacrifice

Sacrifice is the offering of food, objects or the lives of animals or people to God or the gods as an act of propitiation or worship.While sacrifice often implies ritual killing, the term offering can be used for bloodless sacrifices of cereal food or artifacts...

 (yajna

Yajna

In Hinduism, yajna is a ritual of sacrifice derived from the practice of Vedic times. It is performed to please the gods or to attain certain wishes...

) or ritual

Ritual

A ritual is a set of actions, performed mainly for their symbolic value. It may be prescribed by a religion or by the traditions of a community. The term usually excludes actions which are arbitrarily chosen by the performers....

 in Vedic Religion

Historical Vedic religion

The religion of the Vedic period is a historical predecessor of Hinduism. Its liturgy is reflected in the mantra portion of the four Vedas, which are compiled in Sanskrit. The religious practices centered on a clergy administering rites...

, The word is so used in the Rigveda

Rigveda

The Rigveda is an ancient Indian sacred collection of Vedic Sanskrit hymns...

, the Yajurveda

Yajurveda

The Yajurveda, a tatpurusha compound of "sacrificial formula', + ) is the third of the four canonical texts of Hinduism, the Vedas. By some, it is estimated to have been composed between 1400 and 1000 BC, the Yajurveda 'Samhita', or 'compilation', contains the liturgy needed to perform the...

 and the Atharvaveda

Atharvaveda

The Atharvaveda is a sacred text of Hinduism and one of the four Vedas, often called the "fourth Veda"....

. In Classical Sanskrit, it refers to an epoch or period, especially one of the six seasons or ritus in the Hindu calendar

Hindu calendar

The hindu calendar used in ancient times has undergone many changes in the process of regionalization, and today there are several regional Indian calendars, as well as an Indian national calendar. Nepali calendar, Bengali calendar, Malayalam calendar, Tamil calendar, Telugu calendar, Kannada...

, Vasanta/Basant "spring", Grishma

Grishma

Grishma is short for Grishmarutu, the Sankrit word meaning summer . This is one of the six seasons,each lasting two months. Grishma is short for Grishmarutu, the Sankrit word meaning summer (as in the season). This is one of the six seasons,each lasting two months. Grishma is short for...

 "the hot season", Varsha

Varsha

Varsha may refer to:* Varsha, Rainy season or ritu in Hindu calendar-Given names:*Bob Varsha, American sports announcer*Varsha Bhosle, Indian journalist*Varsha Soni, Indian field hockey player*Varsha Usgaonkar, Indian actress...

 "the rainy season", Sharad

Sharad

Sharad in North India, variantly referred to as Sharat or Sharath or Sarath in South India, is the early autumn ritu, or season in the Hindu calendar. It roughly corresponds to the western months of mid-September to mid-November. Sharad is preceded by Varsha, followed by Hemant...

 "autumn", Hemant "winter"; and Shishir

Shishir

Shishir in Hindu calendar is the season or Ritu, related to winters and cold. It is also one among the many names of the Hindu God Lord Vishnu,and appears in the Vishnu sahasranama , and hence also a given name for boys. it is the month of Magha and Phalguna or mid January to mid march in the...

 "the cool season", or the menstrual cycle.

It is also the name of a Rishi

Rishi

Rishi denotes the composers of Vedic hymns. However, according to post-Vedic tradition, the rishi is a "seer" to whom the Vedas were "originally revealed" through states of higher consciousness. The rishis were prominent when Vedic Hinduism took shape, as far back as some three thousand years...

 and of the 12th Manu

Manu (Hinduism)

In various Hindu traditions, Manu is a title accorded to the progenitor of mankind, and also the very first brahman king to rule this earth, who saved mankind from the universal flood. He was absolutely honest which was why he was initially known as "Satyavrata"...

.

Rtu in its diverse meanings can also be associated with food as is described in the Rig Veda. Hymn 15 Book 1.