Blót (Old Norse and Old English) or geblōt (Old English) are religious ceremonies in Germanic paganism that centred on the killing and offering of an animal to a particular being, typically followed by the communal cooking and eating of its meat. Old Norse sources present it as a central ritual in Old Nordic religion that was intimately connected with many wider aspects of life. Large blót are often described as taking place in halls, organised by the rulers of the region who were expected to carry out the practice on behalf of the people. Blót were central to the legitimacy of rulers and Christian rulers refusing to hold them were at times replaced by more willing alternatives and driven out of the land. Smaller, household blót were sometimes recorded as being led by women. Beyond strengthening legitimacy for the ruling elites, the performance of blót was often to ensure the fertility of the land, a good harvest and peace, although they are also recorded as being performed for divination or to achieve desired results in legal matters.

After the establishment of Christianity, blót were routinely made punishable offences, as seen in early Germanic legal codes, with the recipients of the worship and sacrifice often equated with demons. Despite this, some aspects of the practice were likely incorporated into local Christian culture and continued into the modern period. The conscious performing of blót has also been revived in the modern period as part of the practice of modern heathens.

The verb form is seen in Old Norse: blóta ("to worship; to sacrifice"), Gothic: blotan ("to serve (God); to worship"; to honour (through sacrifice)"), Old English: blōtan ("to sacrifice") and Old High German: blōzan. The Proto-Germanic form of the verb can be reconstructed as the strong verb *blōtanan, or *blōtan meaning "to sacrifice".

The noun form is seen in Old English: blót and ge-blót ("sacrifice"), and Old Norse: blót ("sacrifice; worship"). A Proto-Germanic form of the noun can be similarly reconstructed as *blōtan. A similar and related form can be reconstructed as *blōtan from Old High German: bluostar ("sacrifice") and Gothic: blostreis, a component of guþ-blostreis ("worshipper of God"). Blót can also be used to mean "idol-worship" in general, an "idol" (often in the form blœti) or metaphorically to mean "cursing" or "swearing" in Christian times due to the negative view of heathenry.

The shared Germanic root has been proposed to be related to *blōtan ("to blow; to bloom; to blossom"), which is further connected to *blōđan ("blood"). A connection has been further proposed to Latin: flamen ("priest"), although it has been argued that the validity of this is dependent on the exact root of flamen which cannot be determined with certainty.

In the context of "to worship" or "to worship with sacrifice", the Old Norse verb blóta is typically used with that being worshipped in the accusative case, and rarely with it in the dative case. The dative case is more typically used for the object being sacrificed. The verb is often followed by the aim of the blót, for example til friðar, sigrs, langlífis, árs, byrjar ("for peace, victory, long life, good season, fair wind").

Old Norse: Blót is found in many compound words relating to worship or sacrifice. These include adjectives such as blót-auðigr ("rich in sacrifices") and terms for individuals also include it is a prefix such as blót-biskup, blót-kennimaðr, or blót-goði ("heathen priest"), blót-hofðingi ("heathen chief"). Other compounds include recipients of worship such as blót-guð ("heathen god") and blót-kálfr ("calf worshipped with sacrifices"). Items with religious function can also include it as a prefix such as blót-bolli ("sacrificial bowl") and blót-klæði ("garments worn at sacrifices"), and it can refer to religious concepts such as blót-dómr or blót-skapr ("idolatry"), and blótnaðr which is used to mean both "sacrificing to heathen gods" and "idolatry".

It has been proposed that during the Migration Period, religious organisation drastically changed, with rulers gaining enough power to centralise sacrifices and ceremonies to their own homes rather than in outdoor spaces such as bogs and lakes, as had been done before. These indoor cultic buildings are referred to in Old Norse sources variously as hof, hǫrgar, goðahús, blóthús.