この記事では語源bi（2）に関連する英単語を紹介します。
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bicycle /bάɪsɪkl/ : 自転車
bicycleは「自転車」を意味し、語源はbi（２）とkyklos（車輪）に由来します。口語表現はbikeです。
Bicycle means “a vehicle with two wheels”, and the etymology comes from bi (two) and kyklos (wheel). The colloquial expression is bike. Let’s see example sentences of bicycle.
If the company is close to home, we can commute by bicycle. You can train leg strength by pedaling a bicycle. Always lock the bicycle when you park it. If the tire of the bicycle is punctured, let’s have it repaired at the cycling shop. Weak elderly people move around the city by electric bicycle. The sports gym is equipped with a bicycle for training.
biennial /bὰɪéniəl/ : 二年生の
biennialは「二年に一回」を意味し、語源はbi（２）とannus（年）に由来します。biennialは植物学でよく使われます。
Biennial means “once in two years”, and the etymology comes from bi (2) and annus (year). Biennial is often used in botany. Biennial plants are plants with a lifespan of 2 years, and fewer than annual and perennial plants. Examples of biennial plants include sugar beet, cabbage, lettuce, and parsley.
bigamy /bígəmi/ : 重婚
bigamyは「重婚」を意味し、語源はbi（２）とgamos（結婚）に由来します。
ほとんどの国では一夫一婦制が採用されており、重婚は法律で禁止されています。
Bigamy means “marriage to two people at the same time”, and the etymology comes from bi (ii) and gamos (marriage).
Most countries adopt monogamy, and bigamy is prohibited by law. Japanese civil law also stipulates that “a person with a spouse can not marry repeatedly.” In Islamic country countries, bigamy (polygamy system) is allowed, but the government impose conditions: that they have enough income to support their wives and that they treat their wives equally.
bilingual /bὰɪlíŋgwəl/ : 二カ国語を使う
bilingualは「二ヶ国語を使うこと」を意味し、語源はbi（２）とlingual（舌の）に由来します。
Bilingual means “using two languages”, and the etymology comes from bi (2) and lingual (tongue). Let’s see example sentence of bilingual.
This site you are reading now is a site using English and Japanese bilingual. Schools that hold up globalization adopt bilingual education. Children with American and Japanese parents can speak English and Japanese bilingual. English-Japanese dictionary and Japanese-English dictionary are bilingual dictionaries.
binary /bάɪnəri/ : 二進法の
binaryは「二進法」を意味し、語源はbinarius（二つから成る）に由来します。
二進法とは０と１だけで数を数える方法です。例えば十進法なら０、１、２、３と数字を数えますが、二進法なら０、１、１０、１１と数えます。
Binary means “a system of counting where number 0 and 1 are used”, and the etymology comes from binarius (consisting of two).
Binary system is a method of counting numbers by only 0 and 1. For example, in decimal system, we count numbers as 0, 1, 2, 3, but in binary notation we counts as 0, 1, 10, 11. The binary system is intuitively difficult for humans to understand, but it is very easy to understand for digital equipment. Digital equipment is compatible with binary system because it calculates by using two physical phenomena such as high and low of voltage and S pole · N pole of magnetic force.
Binary options are a kind of exchange finance products. We expect to see if the price goes up or down after a few hours. If we expected correctly, we get profits. Unlike FX, binary option seems to be a low risk because it uses no leverage and no pursuit. However, repeating transactions in a short period of time can increase the amount of loss. Furthermore, swindlers use binary option as a tool of fraud and run away with user’s funds. The National Lifestyle Center is calling attention.
binoculars /bὰɪnάkjəlɚ/ : 双眼鏡
binocularsは「双眼鏡」を意味し、語源はbini（二つからなる）とoculus（目）に由来します。
Binoculars means “optical device to see at a distance”, and the etymology comes from bini (consisting of two) and oculus (eyes).
Binoculars are optical instruments for seeing distant objects. Binoculars are mainly used for sports watching and bird watching. Using a binocular for peeping is a crime. Specifications of binoculars are written as 7 × 50, 7 is magnification, and 50 is the diameter of the objective lens. If the magnification is high, you can see distant objects, and the longer the diameter of the objective lens, the brighter the field of view.
bipolar /bὰɪpóʊlɚ/ : 双極性の
bipolarは「二極性の」という意味で、語源はbi（二）とpolar（極の）に由来します。
bipolarは主に精神疾患で使われます。双極性障害は気分が高まった「躁状態」と落ち込んだ「うつ状態」を繰り返す精神病です。
Bipolar means “manic depression”, and the etymology comes from bi (2) and polar.
Bipolar is mainly used for mental illness. Bipolar disorder is a psychosis that repeats “manic state” in excited mood and “depressed state” in depressed mood. The disease name comes from the mental state going to and from both extremes.
The cause of bipolar disorder is greatly influenced by heredity. The lifetime prevalence of Japanese bipolar disorder is 0.2%, and it is very low compared with 3% of world average. The common therapy for bipolar disorder is using mood stabilizers and interpersonal social rhythm therapy.