The meaning of 600 Dutch words that contain the vowels A, A and O, such as in ‘vagabond’ or ‘catacombs’, were compared in several languages. AAO-translations of Dutch AAO-words were examined in Hungarian (HG), Italian (IT) and Spanish (SP). In a lesser degree were used: English (EN), French (FR), Old and Modern Greek (OG and MG), Latin (LT), Romanian (RH), Polish (PL), Serbo-Croatian (SK) and Turkish (TS). This research of F. Alpaerts (1984) shows a connection between the triplet vowels AAO, and the colour combination black-on-blue. Because some keywords are related, Alpaerts classified them into themed clusters.

1. Attack: The direct physical violence. The threat to property (robbery, looting, mugging). The physical and psychological attack on the body (disease, infection by impurity). Psychic attacks (abrasive, rancor). Attacks on the social body: violating social purity rules (inappropriate behavior, swearing, sexual offenses). Attack on the culture (immigration, marginality, and poverty).
2. Death (religious): The boundary of life (death). The dying (illness, diseased, weary). The abode of the dead (tombs, catacombs, cemeteries). The cult of the dead (Pharaohs, ancestor worship, funeral rites).
3. Haggler (costly, money, wasteful). Fear of loss of property is agony.
4. Border (maggoty, wasteland, abandoned, vagabond). Crossing borders, whether national, social, cultural, or regarding the body or property are associated with contamination and death.
5. Braggart (make an impression)
6. Rest and unrest (lying down, anchor, stampede, mass movement, large-scale events). Rest in the sense of lying down, doing nothing, either through illness, death, vacation, or unemployment. Doing nothing is caused by external factors that are considered a constraint. Unrest shows itself in major events that bring masses of people together: social commemorations, music events, war.
7. Conceal (locksmith). That which lies behind the border or which one hides from attackers.
8. Embrace. Not a loving embrace, but clamping down on property to protect it from robbers (see also Haggler and Conceal). Stuffed bag, or suitcase, money handle, safe.
9. Contamination (dirt, rag, feet, contact with the ground). Contamination by touching contaminated objects, such as the ground, a sick person or a corpse. Contamination of the earth, of our bodies resulting in disease, of the social and cultural body.

Keywords classified in the DSD under the black-on-blue code are:

1. assault, attack, biting, abandoned, curse, rancor, theft, thief
2. ancestor, forefather, body, coffin, final resting, death, the end, grave, urn, graveyard, underground, undertaker, serious, secret, mystery, depressed, old age, disease, sick
3. bill, costly
4. border, boundary, bounded, beggar, wasteland
5. tightwad
6. mass movement
7. concealing, digging, haze
8. embrace, filled
9. contamination, dirt, footprint (dirty), rag, waste, shoes

I. Michiels (red.)