Reeves is entitled to British citizenship through his English mother. He holds Canadian citizenship by naturalization. He grew up as a Canadian and identifies as such, and holds an American green card. Reeves' biological father was born in the United States but Reeves required a green card because he was not eligible to claim automatic citizenship by birth abroad to one United States citizen.
In January 2000, Reeves's girlfriend, Jennifer Syme, gave birth eight months into her pregnancy to Ava Archer Syme-Reeves, who was stillborn. The strain put on their relationship by their grief resulted in Reeves and Syme's breakup several weeks later. On April 2, 2001, Syme was driving alone on Los Angeles' Cahuenga Boulevard when she sideswiped three parked cars, rolled over several times and was thrown from the car. Authorities believed she died instantly. She reportedly was being treated for depression and taking two prescription drugs, which police found in her car. Reeves, who was scheduled to begin shooting back-to-back Matrix sequels during the subsequent spring, sought "peace and time to deal with this", according to his friend Bret Domrose, a guitarist in Reeves's alternative rock band Dogstar.
Reeves has been described as atheist and as having interest in Buddhism. He has previously said he is non-religious and not a Buddhist, but has mentioned an interest in Buddhism when studying for certain film roles. In September 2013, when asked if he was a spiritual person, he replied with: "I don't know? I don't know the spiritual Richter-scale measurement! That's a weird answer, isn't it? I don't know. Do I believe in God, faith, inner faith, the self, passion, and things? Yes, of course! I'm very spiritual ... Supremely spiritual ... Bountifully spiritual ... Supremely bountiful. [Laughs.]"
In 2010, an image of Reeves became an internet meme after photos of him, seemingly depressed while sitting on a park bench eating alone, were posted to a 4chan forum. The images were soon distributed via several blogs and news sites. These pictures led to the "Keanu is Sad" or "Sad Keanu" meme being spread on internet forums. An unofficial holiday was created when a Facebook fan page declared June 15 as "Cheer-up Keanu Day". On the first anniversary of "Cheer-up Keanu Day", Reeves was interviewed for an article in British newspaper, The Guardian.
The word kilogramme or kilogram is derived from the French kilogramme, which itself was a learned coinage, prefixing the Greek stem of khilioi "a thousand" to gramma, a Late Latin term for "a small weight", itself from Greek . The word kilogramme was written into French law in 1795, in the Decree of 18 Germinal, which revised the older system of units introduced by the French National Convention in 1793, where the gravet had been defined as weight (poids) of a cubic centimetre of water, equal to 1/1000 of a grave. In the decree of 1795, the term gramme thus replaced gravet, and kilogramme replaced grave.
The French spelling was adopted in the United Kingdom when the word was used for the first time in English in 1797, with the spelling kilogram being adopted in the United States. In the United Kingdom both spellings are used, with "kilogram" having become by far the more common. UK law regulating the units to be used when trading by weight or measure does not prevent the use of either spelling.
In the 19th century the French word kilo, a shortening of kilogramme, was imported into the English language where it has been used to mean both kilogram and kilometre. While kilo is acceptable in many generalist texts, for example The Economist, its use is typically considered inappropriate in certain applications including scientific, technical and legal writing, where authors should adhere strictly to SI nomenclature. When the United States Congress gave the metric system legal status in 1866, it permitted the use of the word kilo as an alternative to the word kilogram, but in 1990 revoked the status of the word kilo.
During the 19th century, the standard system of metric units was the centimetregramsecond system of units, treating the gram as the fundamental unit of mass and the kilogram simply as a derived unit. In 1901, however, following the discoveries by James Clerk Maxwell to the effect that electric measurements could not be explained in terms of the three fundamental units of length, mass and time, Giovanni Giorgi proposed a new standard system which would include a fourth fundamental unit to measure quantities in electromagnetism. In 1935 this was adopted by the IEC as the Giorgi system, now also known as MKS system, and in 1946 the CIPM approved a proposal to adopt the ampere as the electromagnetic unit of the "MKSA system". In 1948 the CGPM commissioned the CIPM "to make recommendations for a single practical system of units of measurement, suitable for adoption by all countries adhering to the Metre Convention". This led to the launch of SI in 1960 and the subsequent publication of the "SI Brochure", which stated that "It is not permissible to use abbreviations for unit symbols or unit names ...". The CGS and MKS systems co-existed during much of the early-to-mid 20th century, but as a result of the decision to adopt the "Giorgi system" as the international system of units in 1960, the kilogram is now the SI base unit for mass, while the definition of the gram is derived from that of the kilogram.