TL;DR - As a consumer in a Chinese-speaking land, I would be expecting the kernel of a sweet varietal of apricot, Prunus armeniaca.
Permit me to bring in some botany! Plums, cherries, peaches, apricots and almonds, as defined in general Western groceries in English-speaking countries (let us ignore the sloe for now), are all species of Prunus, a genus of drupe-bearing trees in the rose family. The Latin for "plum" gives the genus its scientific name.
李、桃、杏、梅、樱 are all base terms in Chinese for various Prunus species too (let us ignore the commercially less important 橉木). They do not correspond one-to-one with English terms.
Chinese 杏 is sharply distinguished in English: the apricot Prunus armeniaca, cultivated for its fruit, is linguistically differentiated from the almond Prunus dulcis (syn. Prunus amygdalus), cultivated for its kernel as a culinary nut (its fruit is edible, and is commercially cultivated, but in a very minor way in Anglophone countries). The bitter almond is a cultivar Prunus dulcis var. amara, whereas the majority of the world's current (as of 2024) almond production is chanelled into sweet almond production, Prunus dulcis var. dulcis, and is thus the "default" almond.
With modern Chinese agriculture producing both products (although as nations they are generally net importers of both agricultural products), there are ways to distinguish almonds from apricots in modern Chinese. Modern genetic taxonomy generally sees the almond as closer to the peach than to the apricot; this is reflected in the choice of 扁桃 for the almond, although that could be to do with its Persian roots in the word ادام (bâdâm), which has a more direct transliteration 巴旦木. It is thus not surprising that 扁桃 retains a jargonistic tone to it, and that it is not commonly used for the almond.
Nonetheless, across Chinese culture, 杏仁 apricot kernels, of Prunus armeniaca, have been major agricultural products in a way that almond kernels were not until relatively recently (almond plantations in Xinjiang were commercialised only in the 2010s). Apricot kernels do indeed come in sweet and bitter varieties, which as with almonds is related to amygdalin concentrations. Both are commercially sold, 甜杏仁 or 南杏 (the latter being somewhat of a Cantonese-ism) being the sweet apricot kernel and 苦杏仁 or 北杏 (ibid.) being the bitter apricot kernel. It is also not unheard of for the sweet variety to be eaten as a snack, and for both to be used in traditional Chinese medicine. There are many a website (e.g. this company based in Yunlin, Taiwan) that distinguishes the three; and there have been a few American websites that have reported on the relationship between the four of them, in relation to the lack of availability of bitter almond oil.
Note this confusion of botanical semantic fields goes the other way too. 梅 and 李 are generally conflated into English "plum". To distinguish them, the 梅 Prunus mume is often given the moniker "Chinese plum" or "Japanese plum". However, the 梅 is not commercially produced in Western English-speaking countries and holds little commercial or cultural value in those nations, in great contrast to East Asia. Thus the distinction is rarely made.
Genetic studies seem to classify 梅 closer to the "apricot" Prunus armeniaca, hence the more modern name "Japanese (flowering) apricot". This English name avoids confusion with 李, which in turn has its own confusion, but one that is much more easily resolved. In China 李 generally refers to cultivars of Prunus salicina, whereas "plum" in Britain and in Anglophone North America generally refer to various cultivars of Prunus domestica; however, one can specify e.g. 中国李 vs 欧洲李 vs a varietal like 凤凰李, and likewise in English "Chinese / Japanese plum" vs "European / domestic plum" vs a varietal like "greengage".
