Translation of 大日如来寺? I have gotten interested in an esoteric Buddhist school originating from China and I was wondering what "dari rulai" meant. 

I have sort of figured out part of it: "dari" is probably great-day or great-sun. But I cannot figure out "rulai" at all.
大日如來

Mahāvaircana, the Buddha who is the central teacher and object of veneration in Vajrayāna Buddhism (密宗).

"The Great Sun Buddha, is the transcendent and cosmocratic apotheosis of the historical Buddha, Sakyamuni (釋迦牟尼).
Under the earlier designation Vairocana ("the luminous one"), he represents Buddhism's most profound speculation on the emptiness and interpenetration of all elements in the universe (dharmadhātu, 法界).
As Mahāvairocana he is concretely envisaged as the all-encompassing lord of the cosmos and is the object of worship for a form of Tantric Buddhism (密宗) that spread from India to Sumatra, China, Japan, and Tibet."
(Encyclopedia of Religion, Orzech)

Originally the name referred to the light of the sun, but later on took on connotations of the buddha as fundamental principle of the universe.

He is one of the five buddhas 五佛 depicted in the maṇḍalas of the vajradhātu (金剛界) and garbhadhātu (胎藏界).

The name is transcribed into Chinese as 摩訶毗盧遮那 and 毗盧遮那佛, and is translated variously as 最高顯廣眼藏, 遍照王如來, 光明遍照, 大日遍照, 遍一切處, 遍照尊.

Source: 《 English-Chinese-English Dictionary of Buddhist Terms 》



大日如來

梵名 Mahāvairocana 。為密教供奉之本尊與最上根本佛。音譯作摩訶毗盧遮那。又作毗盧遮那佛、最高顯廣眼藏、遍照王如來、光明遍照、大日遍照、遍一切處、遍照尊。

其名有三義，即：
(一)除暗遍明義，謂如來智慧日光遍一切處，作大照明，無有內外、晝夜之別。
(二)眾務成辦義，謂如來日光遍照法界，能平等開發無量眾生之善根，乃至成就世、出世間種種殊勝事業。
(三)光無生滅義，謂佛心之日雖為無明所覆障，而無所減；究竟如法實相三昧圓明，而無所增。
以如此諸種原因，故世間之日不可為喻，但取其少分相似處，故加以‘大’字。

大日如來係密宗將宇宙實相佛格化之根本佛，亦為一切諸佛菩薩所出之本原及所歸之果體；其身口意業遍虛空，演說如來之三密門金剛一乘甚深教。《大日經疏》卷一謂，大日如來分本地法身與加持受用身兩種，其中，本地法身指如來之自證極位，加持受用身指說法之教主；彼以平等之身口意秘密加持為所入之門（即以身平等之密印、語平等之真言、心平等之妙觀為方便），故知加持受用之身即是毗盧遮那遍一切身，此二身畢竟無二無別。故密宗以大日如來為最高之佛格與根本總德。以其與諸法遍在，故密號遍照金剛。

又因大日如來為金、胎兩部曼荼羅之主尊，故非常被重視，其智德以金剛界大日如來表示之，其理德則以胎藏界大日如來表示；理、智雖然二分，實際亦不相離。金剛界大日為金剛界九會中，除理趣會以外之中尊，位於五佛中央，現菩薩形，身呈白色，戴五智寶冠，結智拳印，結跏趺坐於七獅子座，此即智法身。胎藏界大日則為位於中台八葉院中央之理法身，亦現菩薩形，身呈黃金色，頭戴五佛寶冠，結法界定印，坐於八葉蓮華台上。

Source: 《佛光大辭典》



如來 Tathāgata (तथागत), 多陀阿伽陀.

Tathāgata (怛他揭多) defined as he who comes as do all other Buddhas; or as he who took the 真如 zhenru or absolute way of cause and effect, and attained to perfect wisdom; or as the absolute come; one of the highest titles of a Buddha. 

It is the Buddha in his nirmāṇakāya (निर्माणकाय), i. e. his 'transformation' or corporeal manifestation descended on earth. The two kinds of Tathāgata are (1) 在纏 the Tathāgata in bonds, i. e. limited and subject to the delusions and sufferings of life, and (2) 出纏 unlimited and free from them.

There are numerous sutras and śāstras bearing this title of 如來 (rulai).

Source: 《 Soothill-Hodous Dictionary of Chinese Buddhist Terms 》